From 22df5d37a2c3d28d6bcab5e97a0c9f6a95f33bbc Mon Sep 17 00:00:00 2001
From: aman035 <guptaaman200115@gmail.com>
Date: Wed, 12 Aug 2026 15:58:17 +0530
Subject: [PATCH 1/4] fix: guard confirmation depth against RPC height skew;
 gate zero-confirmation instant routes to testnet (F-2026-18139)

---
 universalClient/chains/chains.go              |  4 +-
 universalClient/chains/common/confirmation.go | 20 +++++
 .../chains/common/confirmation_test.go        | 42 ++++++++++
 universalClient/chains/evm/client.go          | 36 +++++---
 universalClient/chains/evm/client_test.go     | 83 ++++++++++++++++---
 universalClient/chains/evm/event_confirmer.go | 37 +++++----
 .../chains/evm/event_confirmer_test.go        | 14 ++--
 universalClient/chains/svm/client.go          | 42 +++++++---
 universalClient/chains/svm/client_test.go     | 79 +++++++++++++-----
 universalClient/chains/svm/event_confirmer.go | 36 ++++----
 .../chains/svm/event_confirmer_test.go        | 24 +++---
 universalClient/chains/svm/rpc_client.go      |  1 +
 universalClient/config/config_test.go         | 25 ++++++
 universalClient/config/default_config.json    |  1 +
 universalClient/config/types.go               | 29 ++++++-
 15 files changed, 369 insertions(+), 104 deletions(-)
 create mode 100644 universalClient/chains/common/confirmation.go
 create mode 100644 universalClient/chains/common/confirmation_test.go

diff --git a/universalClient/chains/chains.go b/universalClient/chains/chains.go
index bb0b102bc..254131316 100644
--- a/universalClient/chains/chains.go
+++ b/universalClient/chains/chains.go
@@ -278,9 +278,9 @@ func (c *Chains) addChain(ctx context.Context, cfg *uregistrytypes.ChainConfig)
 	var client common.ChainClient
 	switch cfg.VmType {
 	case uregistrytypes.VmType_EVM:
-		client, err = evm.NewClient(cfg, chainDB, chainConfig, c.pushSigner, c.logger)
+		client, err = evm.NewClient(cfg, chainDB, chainConfig, c.pushSigner, c.config.AllowsZeroConfirmations(), c.logger)
 	case uregistrytypes.VmType_SVM:
-		client, err = svm.NewClient(cfg, chainDB, chainConfig, c.pushSigner, c.config.NodeHome, c.logger)
+		client, err = svm.NewClient(cfg, chainDB, chainConfig, c.pushSigner, c.config.NodeHome, c.config.AllowsZeroConfirmations(), c.logger)
 	default:
 		return fmt.Errorf("unsupported VM type: %v", cfg.VmType)
 	}
diff --git a/universalClient/chains/common/confirmation.go b/universalClient/chains/common/confirmation.go
new file mode 100644
index 000000000..0ba4e8437
--- /dev/null
+++ b/universalClient/chains/common/confirmation.go
@@ -0,0 +1,20 @@
+package common
+
+// ConfirmationDepth returns the number of confirmations for a transaction
+// observed at txHeight against a chain tip at latestHeight, defined as
+// latestHeight - txHeight + 1 (the inclusion block counts as one confirmation).
+//
+// ok is false when latestHeight < txHeight. That ordering is not physically
+// possible on a single consistent view of a chain, but the latest-height and
+// transaction reads are independent RPC calls that the pool round-robins across
+// endpoints. When the endpoint serving the transaction is ahead of the one
+// serving the tip, an unchecked latestHeight - txHeight underflows uint64 to a
+// value near 2^64 and satisfies any confirmation threshold, prematurely
+// finalizing an inbound. Callers must treat ok == false as "defer, still
+// pending" rather than trusting the returned depth.
+func ConfirmationDepth(latestHeight, txHeight uint64) (depth uint64, ok bool) {
+	if latestHeight < txHeight {
+		return 0, false
+	}
+	return latestHeight - txHeight + 1, true
+}
diff --git a/universalClient/chains/common/confirmation_test.go b/universalClient/chains/common/confirmation_test.go
new file mode 100644
index 000000000..b50afbabc
--- /dev/null
+++ b/universalClient/chains/common/confirmation_test.go
@@ -0,0 +1,42 @@
+package common
+
+import (
+	"math"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestConfirmationDepth(t *testing.T) {
+	tests := []struct {
+		name      string
+		latest    uint64
+		tx        uint64
+		wantDepth uint64
+		wantOK    bool
+	}{
+		{"latest greater than tx", 110, 100, 11, true},
+		{"latest equals tx (inclusion block)", 100, 100, 1, true},
+		{"latest one below tx (skew)", 99, 100, 0, false},
+		{"latest far below tx (skew)", 1, math.MaxUint64, 0, false},
+		{"no underflow to near-2^64", 0, 1, 0, false},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			depth, ok := ConfirmationDepth(tc.latest, tc.tx)
+			assert.Equal(t, tc.wantOK, ok)
+			assert.Equal(t, tc.wantDepth, depth)
+		})
+	}
+}
+
+// TestConfirmationDepth_SkewNeverSatisfiesThreshold guards the exact finding:
+// a transaction one block ahead of the observed tip must not produce a depth
+// that clears a realistic confirmation threshold.
+func TestConfirmationDepth_SkewNeverSatisfiesThreshold(t *testing.T) {
+	const threshold = uint64(12)
+	depth, ok := ConfirmationDepth(500, 501)
+	assert.False(t, ok, "skewed read must be flagged not-ok")
+	assert.False(t, depth >= threshold, "skewed depth must not satisfy threshold")
+}
diff --git a/universalClient/chains/evm/client.go b/universalClient/chains/evm/client.go
index 80c7f1500..bf3a9aab6 100644
--- a/universalClient/chains/evm/client.go
+++ b/universalClient/chains/evm/client.go
@@ -20,10 +20,11 @@ import (
 // Client implements the ChainClient interface for EVM chains
 type Client struct {
 	// Core configuration
-	logger         zerolog.Logger
-	chainIDStr     string
-	registryConfig *uregistrytypes.ChainConfig
-	chainConfig    *config.ChainSpecificConfig
+	logger                 zerolog.Logger
+	chainIDStr             string
+	registryConfig         *uregistrytypes.ChainConfig
+	chainConfig            *config.ChainSpecificConfig
+	allowZeroConfirmations bool
 
 	// Infrastructure
 	rpcClient *RPCClient
@@ -49,6 +50,7 @@ func NewClient(
 	database *db.DB,
 	chainConfig *config.ChainSpecificConfig,
 	pushSigner *pushsigner.Signer,
+	allowZeroConfirmations bool,
 	logger zerolog.Logger,
 ) (*Client, error) {
 	if config == nil {
@@ -68,12 +70,13 @@ func NewClient(
 	}
 
 	client := &Client{
-		logger:         log,
-		chainIDStr:     chainIDStr,
-		registryConfig: config,
-		chainConfig:    chainConfig,
-		database:       database,
-		pushSigner:     pushSigner,
+		logger:                 log,
+		chainIDStr:             chainIDStr,
+		registryConfig:         config,
+		chainConfig:            chainConfig,
+		allowZeroConfirmations: allowZeroConfirmations,
+		database:               database,
+		pushSigner:             pushSigner,
 	}
 
 	client.eventCleaner = common.NewEventCleaner(
@@ -381,6 +384,19 @@ func (c *Client) applyDefaults() componentConfig {
 		config.standardConfirmations = uint64(c.registryConfig.BlockConfirmation.StandardInbound)
 	}
 
+	// A registry-configured 0 disables the reorg-safety depth (confirm at the
+	// inclusion block). Honor it only when zero-confirmation mode is explicitly
+	// enabled (testnet instant routes); otherwise fall back to a safe default so
+	// mainnet cannot silently finalize inbounds prematurely. See F-2026-18139.
+	if !c.allowZeroConfirmations {
+		if config.fastConfirmations == 0 {
+			config.fastConfirmations = 2
+		}
+		if config.standardConfirmations == 0 {
+			config.standardConfirmations = 12
+		}
+	}
+
 	return config
 }
 
diff --git a/universalClient/chains/evm/client_test.go b/universalClient/chains/evm/client_test.go
index 1ea67b10c..31ef5cabe 100644
--- a/universalClient/chains/evm/client_test.go
+++ b/universalClient/chains/evm/client_test.go
@@ -36,7 +36,7 @@ func TestClientInitialization(t *testing.T) {
 		}
 
 		chainSpecificConfig := testChainConfig([]string{"https://eth-mainnet.example.com"})
-		client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, logger)
+		client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, false, logger)
 		require.NoError(t, err)
 		assert.NotNil(t, client)
 		assert.Equal(t, chainConfig, client.GetConfig())
@@ -44,7 +44,7 @@ func TestClientInitialization(t *testing.T) {
 	})
 
 	t.Run("Nil config", func(t *testing.T) {
-		client, err := NewClient(nil, nil, nil, nil, logger)
+		client, err := NewClient(nil, nil, nil, nil, false, logger)
 		assert.Error(t, err)
 		assert.Nil(t, client)
 		assert.Contains(t, err.Error(), "config is nil")
@@ -57,7 +57,7 @@ func TestClientInitialization(t *testing.T) {
 		}
 
 		chainSpecificConfig := testChainConfig([]string{})
-		client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, logger)
+		client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, false, logger)
 		assert.Error(t, err)
 		assert.Nil(t, client)
 		assert.Contains(t, err.Error(), "no RPC URLs configured")
@@ -69,7 +69,7 @@ func TestClientInitialization(t *testing.T) {
 			VmType: uregistrytypes.VmType_SVM, // Wrong VM type
 		}
 
-		client, err := NewClient(chainConfig, nil, nil, nil, logger)
+		client, err := NewClient(chainConfig, nil, nil, nil, false, logger)
 		assert.Error(t, err)
 		assert.Nil(t, client)
 		assert.Contains(t, err.Error(), "invalid VM type for EVM client")
@@ -177,7 +177,7 @@ func TestClientStartStop(t *testing.T) {
 		}
 
 		chainSpecificConfig := testChainConfig([]string{server.URL})
-		client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, logger)
+		client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, false, logger)
 		require.NoError(t, err)
 
 		ctx := context.Background()
@@ -199,7 +199,7 @@ func TestClientStartStop(t *testing.T) {
 
 		chainSpecificConfig := testChainConfig([]string{"http://invalid.localhost:99999"})
 
-		client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, logger)
+		client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, false, logger)
 		require.NoError(t, err)
 
 		// Use context with timeout to ensure fast failure
@@ -238,7 +238,7 @@ func TestClientStartStop(t *testing.T) {
 
 		// Use valid URL but cancel context immediately
 		chainSpecificConfig := testChainConfig([]string{server.URL})
-		client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, logger)
+		client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, false, logger)
 		require.NoError(t, err)
 
 		ctx, cancel := context.WithCancel(context.Background())
@@ -295,7 +295,7 @@ func TestClientIsHealthy(t *testing.T) {
 		}
 
 		chainSpecificConfig := testChainConfig([]string{server.URL})
-		client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, logger)
+		client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, false, logger)
 		require.NoError(t, err)
 
 		// Start the client
@@ -320,7 +320,7 @@ func TestClientIsHealthy(t *testing.T) {
 		// Provide valid RPC URLs for NewClient to succeed
 		// But don't start the client
 		chainSpecificConfig := testChainConfig([]string{"https://eth-mainnet.example.com"})
-		client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, logger)
+		client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, false, logger)
 		require.NoError(t, err)
 
 		healthy := client.IsHealthy()
@@ -431,6 +431,65 @@ func TestApplyDefaults(t *testing.T) {
 	})
 }
 
+// TestApplyDefaults_ZeroConfirmations covers the zero-confirmation policy from
+// F-2026-18139: a registry-configured 0 must fall back to a safe depth on
+// mainnet (allowZeroConfirmations=false) and be honored as an instant route
+// only on testnet (allowZeroConfirmations=true).
+func TestApplyDefaults_ZeroConfirmations(t *testing.T) {
+	logger := zerolog.New(zerolog.NewTestWriter(t))
+
+	zeroRegistry := &uregistrytypes.ChainConfig{
+		BlockConfirmation: &uregistrytypes.BlockConfirmation{
+			FastInbound:     0,
+			StandardInbound: 0,
+		},
+	}
+
+	t.Run("mainnet falls back to safe depth", func(t *testing.T) {
+		client := &Client{
+			logger:                 logger,
+			chainIDStr:             "eip155:1",
+			registryConfig:         zeroRegistry,
+			allowZeroConfirmations: false,
+		}
+
+		cfg := client.applyDefaults()
+		assert.Equal(t, uint64(2), cfg.fastConfirmations, "zero fast must not disable depth on mainnet")
+		assert.Equal(t, uint64(12), cfg.standardConfirmations, "zero standard must not disable depth on mainnet")
+	})
+
+	t.Run("testnet honors zero as instant", func(t *testing.T) {
+		client := &Client{
+			logger:                 logger,
+			chainIDStr:             "eip155:1",
+			registryConfig:         zeroRegistry,
+			allowZeroConfirmations: true,
+		}
+
+		cfg := client.applyDefaults()
+		assert.Equal(t, uint64(0), cfg.fastConfirmations, "testnet instant route keeps zero")
+		assert.Equal(t, uint64(0), cfg.standardConfirmations, "testnet instant route keeps zero")
+	})
+
+	t.Run("nonzero registry values unaffected by flag", func(t *testing.T) {
+		client := &Client{
+			logger:     logger,
+			chainIDStr: "eip155:1",
+			registryConfig: &uregistrytypes.ChainConfig{
+				BlockConfirmation: &uregistrytypes.BlockConfirmation{
+					FastInbound:     3,
+					StandardInbound: 9,
+				},
+			},
+			allowZeroConfirmations: false,
+		}
+
+		cfg := client.applyDefaults()
+		assert.Equal(t, uint64(3), cfg.fastConfirmations)
+		assert.Equal(t, uint64(9), cfg.standardConfirmations)
+	})
+}
+
 // TestGetTxBuilderNil tests GetTxBuilder when txBuilder is not initialized
 func TestGetTxBuilderNil(t *testing.T) {
 	logger := zerolog.New(zerolog.NewTestWriter(t))
@@ -441,7 +500,7 @@ func TestGetTxBuilderNil(t *testing.T) {
 	}
 
 	chainSpecificConfig := testChainConfig([]string{"https://eth-mainnet.example.com"})
-	client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, logger)
+	client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, false, logger)
 	require.NoError(t, err)
 
 	// txBuilder is nil because gateway is not configured / Start not called
@@ -464,7 +523,7 @@ func TestClientGetMethods(t *testing.T) {
 	}
 
 	chainSpecificConfig := testChainConfig([]string{"https://eth-sepolia.example.com"})
-	client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, logger)
+	client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, false, logger)
 	require.NoError(t, err)
 
 	t.Run("ChainID", func(t *testing.T) {
@@ -496,7 +555,7 @@ func TestClientConcurrency(t *testing.T) {
 	}
 
 	chainSpecificConfig := testChainConfig([]string{server.URL})
-	client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, logger)
+	client, err := NewClient(chainConfig, nil, chainSpecificConfig, nil, false, logger)
 	require.NoError(t, err)
 
 	ctx := context.Background()
diff --git a/universalClient/chains/evm/event_confirmer.go b/universalClient/chains/evm/event_confirmer.go
index c30039040..df72289f7 100644
--- a/universalClient/chains/evm/event_confirmer.go
+++ b/universalClient/chains/evm/event_confirmer.go
@@ -160,7 +160,19 @@ func (ec *EventConfirmer) processPendingEvents(ctx context.Context) error {
 
 		// Check if transaction is confirmed based on confirmation type
 		requiredConfirmations := ec.getRequiredConfirmations(event.ConfirmationType)
-		confirmations := latestBlock - receipt.BlockNumber.Uint64() + 1
+		txBlock := receipt.BlockNumber.Uint64()
+		confirmations, ok := chaincommon.ConfirmationDepth(latestBlock, txBlock)
+		if !ok {
+			// Cross-RPC height skew: the endpoint that served the receipt is
+			// ahead of the one that served the latest block. Defer rather than
+			// trust a wrapped depth; a later poll with a consistent view resolves it.
+			ec.logger.Warn().
+				Str("event_id", event.EventID).
+				Uint64("latest_block", latestBlock).
+				Uint64("tx_block", txBlock).
+				Msg("latest block behind tx block (RPC height skew); deferring confirmation")
+			continue
+		}
 
 		if confirmations >= requiredConfirmations {
 			var rowsAffected int64
@@ -245,24 +257,17 @@ func (ec *EventConfirmer) getTxHashFromEventID(eventID string) string {
 	return parts[0]
 }
 
-// getRequiredConfirmations returns the required number of confirmations based on confirmation type
+// getRequiredConfirmations returns the required number of confirmations based on
+// confirmation type. The values are already resolved by the client's
+// applyDefaults (registry value, or a safe fallback when the registry is 0 and
+// zero-confirmation mode is not enabled), so a 0 here is an intentional instant
+// route and is honored as-is.
 func (ec *EventConfirmer) getRequiredConfirmations(confirmationType string) uint64 {
 	switch confirmationType {
 	case store.ConfirmationFast:
-		if ec.fastConfirmations >= 0 {
-			return ec.fastConfirmations
-		}
-		return 5
-	case store.ConfirmationStandard:
-		if ec.standardConfirmations >= 0 {
-			return ec.standardConfirmations
-		}
-		return 12
+		return ec.fastConfirmations
 	default:
-		// Default to standard if unknown
-		if ec.standardConfirmations >= 0 {
-			return ec.standardConfirmations
-		}
-		return 12
+		// Standard and unknown types both use the standard depth.
+		return ec.standardConfirmations
 	}
 }
diff --git a/universalClient/chains/evm/event_confirmer_test.go b/universalClient/chains/evm/event_confirmer_test.go
index 221729dd8..d1f331067 100644
--- a/universalClient/chains/evm/event_confirmer_test.go
+++ b/universalClient/chains/evm/event_confirmer_test.go
@@ -375,25 +375,29 @@ func TestEventConfirmer_PendingEventsWithBlockHeightZero(t *testing.T) {
 	assert.Equal(t, uint64(0), pending[0].BlockHeight)
 }
 
+// The confirmer honors whatever depth it is given: the safe-fallback vs
+// zero-confirmation policy is resolved upstream in the client's applyDefaults
+// (see TestApplyDefaults_ZeroConfirmations). A 0 here is an intentional instant
+// route. Regression for F-2026-18139.
 func TestEventConfirmer_GetRequiredConfirmations_ZeroValues(t *testing.T) {
 	logger := zerolog.Nop()
 
-	t.Run("zero fast confirmations returns 0", func(t *testing.T) {
+	t.Run("zero fast confirmations honored as instant", func(t *testing.T) {
 		ec := NewEventConfirmer(nil, nil, "eip155:1", 5, 0, 12, logger)
 		result := ec.getRequiredConfirmations(store.ConfirmationFast)
 		assert.Equal(t, uint64(0), result)
 	})
 
-	t.Run("zero standard confirmations returns 0", func(t *testing.T) {
+	t.Run("zero standard confirmations honored as instant", func(t *testing.T) {
 		ec := NewEventConfirmer(nil, nil, "eip155:1", 5, 5, 0, logger)
 		result := ec.getRequiredConfirmations(store.ConfirmationStandard)
 		assert.Equal(t, uint64(0), result)
 	})
 
-	t.Run("zero standard with unknown type returns 0", func(t *testing.T) {
-		ec := NewEventConfirmer(nil, nil, "eip155:1", 5, 5, 0, logger)
+	t.Run("unknown type uses standard depth", func(t *testing.T) {
+		ec := NewEventConfirmer(nil, nil, "eip155:1", 5, 5, 7, logger)
 		result := ec.getRequiredConfirmations("INSTANT")
-		assert.Equal(t, uint64(0), result)
+		assert.Equal(t, uint64(7), result)
 	})
 }
 
diff --git a/universalClient/chains/svm/client.go b/universalClient/chains/svm/client.go
index 9e96f95fa..e198cdd4e 100644
--- a/universalClient/chains/svm/client.go
+++ b/universalClient/chains/svm/client.go
@@ -18,11 +18,12 @@ import (
 // Client implements the ChainClient interface for Solana chains
 type Client struct {
 	// Core configuration
-	logger         zerolog.Logger
-	chainIDStr     string
-	genesisHash    string
-	registryConfig *uregistrytypes.ChainConfig
-	chainConfig    *config.ChainSpecificConfig
+	logger                 zerolog.Logger
+	chainIDStr             string
+	genesisHash            string
+	registryConfig         *uregistrytypes.ChainConfig
+	chainConfig            *config.ChainSpecificConfig
+	allowZeroConfirmations bool
 
 	// Infrastructure
 	rpcClient *RPCClient
@@ -51,6 +52,7 @@ func NewClient(
 	chainConfig *config.ChainSpecificConfig,
 	pushSigner *pushsigner.Signer,
 	nodeHome string,
+	allowZeroConfirmations bool,
 	logger zerolog.Logger,
 ) (*Client, error) {
 	if config == nil {
@@ -76,14 +78,15 @@ func NewClient(
 	}
 
 	client := &Client{
-		logger:         log,
-		chainIDStr:     chainIDStr,
-		genesisHash:    genesisHash,
-		registryConfig: config,
-		chainConfig:    chainConfig,
-		database:       database,
-		pushSigner:     pushSigner,
-		nodeHome:       nodeHome,
+		logger:                 log,
+		chainIDStr:             chainIDStr,
+		genesisHash:            genesisHash,
+		registryConfig:         config,
+		chainConfig:            chainConfig,
+		allowZeroConfirmations: allowZeroConfirmations,
+		database:               database,
+		pushSigner:             pushSigner,
+		nodeHome:               nodeHome,
 	}
 
 	client.eventCleaner = common.NewEventCleaner(
@@ -408,6 +411,19 @@ func (c *Client) applyDefaults() componentConfig {
 		config.standardConfirmations = uint64(c.registryConfig.BlockConfirmation.StandardInbound)
 	}
 
+	// A registry-configured 0 disables the reorg-safety depth (confirm at the
+	// inclusion slot). Honor it only when zero-confirmation mode is explicitly
+	// enabled (testnet instant routes); otherwise fall back to a safe default so
+	// mainnet cannot silently finalize inbounds prematurely. See F-2026-18139.
+	if !c.allowZeroConfirmations {
+		if config.fastConfirmations == 0 {
+			config.fastConfirmations = 5
+		}
+		if config.standardConfirmations == 0 {
+			config.standardConfirmations = 12
+		}
+	}
+
 	return config
 }
 
diff --git a/universalClient/chains/svm/client_test.go b/universalClient/chains/svm/client_test.go
index 50f1084f7..3a2f03a4a 100644
--- a/universalClient/chains/svm/client_test.go
+++ b/universalClient/chains/svm/client_test.go
@@ -35,7 +35,7 @@ func validChainConfig() *uregistrytypes.ChainConfig {
 func TestNewClient_NilConfig(t *testing.T) {
 	logger := zerolog.New(zerolog.NewTestWriter(t))
 
-	client, err := NewClient(nil, nil, nil, nil, "", logger)
+	client, err := NewClient(nil, nil, nil, nil, "", false, logger)
 	assert.Error(t, err)
 	assert.Nil(t, client)
 	assert.Contains(t, err.Error(), "config is nil")
@@ -49,7 +49,7 @@ func TestNewClient_InvalidVMType(t *testing.T) {
 		VmType: uregistrytypes.VmType_EVM, // wrong VM type
 	}
 
-	client, err := NewClient(cfg, nil, nil, nil, "", logger)
+	client, err := NewClient(cfg, nil, nil, nil, "", false, logger)
 	assert.Error(t, err)
 	assert.Nil(t, client)
 	assert.Contains(t, err.Error(), "invalid VM type for Solana client")
@@ -63,7 +63,7 @@ func TestNewClient_InvalidChainID(t *testing.T) {
 		VmType: uregistrytypes.VmType_SVM,
 	}
 
-	client, err := NewClient(cfg, nil, testChainConfig([]string{"https://rpc.example.com"}), nil, "", logger)
+	client, err := NewClient(cfg, nil, testChainConfig([]string{"https://rpc.example.com"}), nil, "", false, logger)
 	assert.Error(t, err)
 	assert.Nil(t, client)
 	assert.Contains(t, err.Error(), "failed to parse chain ID")
@@ -74,7 +74,7 @@ func TestNewClient_NoRPCURLs_NilChainConfig(t *testing.T) {
 
 	cfg := validChainConfig()
 
-	client, err := NewClient(cfg, nil, nil, nil, "", logger)
+	client, err := NewClient(cfg, nil, nil, nil, "", false, logger)
 	assert.Error(t, err)
 	assert.Nil(t, client)
 	assert.Contains(t, err.Error(), "no RPC URLs configured")
@@ -85,7 +85,7 @@ func TestNewClient_NoRPCURLs_EmptySlice(t *testing.T) {
 
 	cfg := validChainConfig()
 
-	client, err := NewClient(cfg, nil, testChainConfig([]string{}), nil, "", logger)
+	client, err := NewClient(cfg, nil, testChainConfig([]string{}), nil, "", false, logger)
 	assert.Error(t, err)
 	assert.Nil(t, client)
 	assert.Contains(t, err.Error(), "no RPC URLs configured")
@@ -103,7 +103,7 @@ func TestNewClient_ValidCreation(t *testing.T) {
 
 	chainSpecific := testChainConfig([]string{"https://api.mainnet-beta.solana.com"})
 
-	client, err := NewClient(cfg, nil, chainSpecific, nil, "/tmp/node", logger)
+	client, err := NewClient(cfg, nil, chainSpecific, nil, "/tmp/node", false, logger)
 	require.NoError(t, err)
 	require.NotNil(t, client)
 
@@ -122,7 +122,7 @@ func TestNewClient_WithDatabase(t *testing.T) {
 	cfg := validChainConfig()
 	chainSpecific := testChainConfig([]string{"https://api.mainnet-beta.solana.com"})
 
-	client, err := NewClient(cfg, database, chainSpecific, nil, "", logger)
+	client, err := NewClient(cfg, database, chainSpecific, nil, "", false, logger)
 	require.NoError(t, err)
 	require.NotNil(t, client)
 	assert.Equal(t, database, client.database)
@@ -134,7 +134,7 @@ func TestChainID(t *testing.T) {
 	cfg := validChainConfig()
 	chainSpecific := testChainConfig([]string{"https://rpc.example.com"})
 
-	client, err := NewClient(cfg, nil, chainSpecific, nil, "", logger)
+	client, err := NewClient(cfg, nil, chainSpecific, nil, "", false, logger)
 	require.NoError(t, err)
 
 	assert.Equal(t, validSVMChainID(), client.ChainID())
@@ -150,7 +150,7 @@ func TestGetConfig(t *testing.T) {
 	}
 	chainSpecific := testChainConfig([]string{"https://rpc.example.com"})
 
-	client, err := NewClient(cfg, nil, chainSpecific, nil, "", logger)
+	client, err := NewClient(cfg, nil, chainSpecific, nil, "", false, logger)
 	require.NoError(t, err)
 
 	got := client.GetConfig()
@@ -164,7 +164,7 @@ func TestGetTxBuilder_NilBeforeStart(t *testing.T) {
 	cfg := validChainConfig()
 	chainSpecific := testChainConfig([]string{"https://rpc.example.com"})
 
-	client, err := NewClient(cfg, nil, chainSpecific, nil, "", logger)
+	client, err := NewClient(cfg, nil, chainSpecific, nil, "", false, logger)
 	require.NoError(t, err)
 
 	txb, err := client.GetTxBuilder()
@@ -179,7 +179,7 @@ func TestIsHealthy_NotStarted(t *testing.T) {
 	cfg := validChainConfig()
 	chainSpecific := testChainConfig([]string{"https://rpc.example.com"})
 
-	client, err := NewClient(cfg, nil, chainSpecific, nil, "", logger)
+	client, err := NewClient(cfg, nil, chainSpecific, nil, "", false, logger)
 	require.NoError(t, err)
 
 	// rpcClient is nil before Start
@@ -192,7 +192,7 @@ func TestStop_BeforeStart(t *testing.T) {
 	cfg := validChainConfig()
 	chainSpecific := testChainConfig([]string{"https://rpc.example.com"})
 
-	client, err := NewClient(cfg, nil, chainSpecific, nil, "", logger)
+	client, err := NewClient(cfg, nil, chainSpecific, nil, "", false, logger)
 	require.NoError(t, err)
 
 	// Calling Stop before Start should not panic
@@ -206,7 +206,7 @@ func TestStop_CalledTwice(t *testing.T) {
 	cfg := validChainConfig()
 	chainSpecific := testChainConfig([]string{"https://rpc.example.com"})
 
-	client, err := NewClient(cfg, nil, chainSpecific, nil, "", logger)
+	client, err := NewClient(cfg, nil, chainSpecific, nil, "", false, logger)
 	require.NoError(t, err)
 
 	// Double stop should be safe
@@ -220,7 +220,7 @@ func TestApplyDefaults_AllDefaults(t *testing.T) {
 	cfg := validChainConfig()
 	chainSpecific := testChainConfig([]string{"https://rpc.example.com"})
 
-	client, err := NewClient(cfg, nil, chainSpecific, nil, "", logger)
+	client, err := NewClient(cfg, nil, chainSpecific, nil, "", false, logger)
 	require.NoError(t, err)
 
 	defaults := client.applyDefaults()
@@ -242,7 +242,7 @@ func TestApplyDefaults_EventPollingOverride(t *testing.T) {
 	}
 
 	cfg := validChainConfig()
-	client, err := NewClient(cfg, nil, chainSpecific, nil, "", logger)
+	client, err := NewClient(cfg, nil, chainSpecific, nil, "", false, logger)
 	require.NoError(t, err)
 
 	defaults := client.applyDefaults()
@@ -261,7 +261,7 @@ func TestApplyDefaults_GasPriceOverride(t *testing.T) {
 	}
 
 	cfg := validChainConfig()
-	client, err := NewClient(cfg, nil, chainSpecific, nil, "", logger)
+	client, err := NewClient(cfg, nil, chainSpecific, nil, "", false, logger)
 	require.NoError(t, err)
 
 	defaults := client.applyDefaults()
@@ -282,7 +282,7 @@ func TestApplyDefaults_BlockConfirmationOverride(t *testing.T) {
 	}
 	chainSpecific := testChainConfig([]string{"https://rpc.example.com"})
 
-	client, err := NewClient(cfg, nil, chainSpecific, nil, "", logger)
+	client, err := NewClient(cfg, nil, chainSpecific, nil, "", false, logger)
 	require.NoError(t, err)
 
 	defaults := client.applyDefaults()
@@ -305,7 +305,7 @@ func TestApplyDefaults_ZeroValueNotApplied(t *testing.T) {
 	}
 
 	cfg := validChainConfig()
-	client, err := NewClient(cfg, nil, chainSpecific, nil, "", logger)
+	client, err := NewClient(cfg, nil, chainSpecific, nil, "", false, logger)
 	require.NoError(t, err)
 
 	defaults := client.applyDefaults()
@@ -315,6 +315,47 @@ func TestApplyDefaults_ZeroValueNotApplied(t *testing.T) {
 	assert.Equal(t, 0, defaults.gasPriceMarkupPercent) // 0 is the default too
 }
 
+// TestApplyDefaults_ZeroConfirmations covers the zero-confirmation policy from
+// F-2026-18139: a registry-configured 0 must fall back to a safe depth on
+// mainnet (allowZeroConfirmations=false) and be honored as an instant route
+// only on testnet (allowZeroConfirmations=true).
+func TestApplyDefaults_ZeroConfirmations(t *testing.T) {
+	logger := zerolog.New(zerolog.NewTestWriter(t))
+
+	zeroRegistry := &uregistrytypes.ChainConfig{
+		BlockConfirmation: &uregistrytypes.BlockConfirmation{
+			FastInbound:     0,
+			StandardInbound: 0,
+		},
+	}
+
+	t.Run("mainnet falls back to safe depth", func(t *testing.T) {
+		client := &Client{
+			logger:                 logger,
+			chainIDStr:             "solana:mainnet",
+			registryConfig:         zeroRegistry,
+			allowZeroConfirmations: false,
+		}
+
+		defaults := client.applyDefaults()
+		assert.Equal(t, uint64(5), defaults.fastConfirmations, "zero fast must not disable depth on mainnet")
+		assert.Equal(t, uint64(12), defaults.standardConfirmations, "zero standard must not disable depth on mainnet")
+	})
+
+	t.Run("testnet honors zero as instant", func(t *testing.T) {
+		client := &Client{
+			logger:                 logger,
+			chainIDStr:             "solana:mainnet",
+			registryConfig:         zeroRegistry,
+			allowZeroConfirmations: true,
+		}
+
+		defaults := client.applyDefaults()
+		assert.Equal(t, uint64(0), defaults.fastConfirmations, "testnet instant route keeps zero")
+		assert.Equal(t, uint64(0), defaults.standardConfirmations, "testnet instant route keeps zero")
+	})
+}
+
 func TestParseSolanaChainID(t *testing.T) {
 	tests := []struct {
 		name        string
@@ -404,7 +445,7 @@ func TestNewClient_FullConfigGetters(t *testing.T) {
 		GasPriceMarkupPercent:       &gasMarkup,
 	}
 
-	client, err := NewClient(cfg, nil, chainSpecific, nil, "/tmp/home", logger)
+	client, err := NewClient(cfg, nil, chainSpecific, nil, "/tmp/home", false, logger)
 	require.NoError(t, err)
 
 	// Verify all getters
diff --git a/universalClient/chains/svm/event_confirmer.go b/universalClient/chains/svm/event_confirmer.go
index c9895ff8c..131e774f1 100644
--- a/universalClient/chains/svm/event_confirmer.go
+++ b/universalClient/chains/svm/event_confirmer.go
@@ -180,7 +180,18 @@ func (ec *EventConfirmer) processPendingEvents(ctx context.Context) error {
 
 		// Check if transaction is confirmed based on confirmation type
 		requiredConfirmations := ec.getRequiredConfirmations(event.ConfirmationType)
-		confirmations := latestSlot - txSlot + 1
+		confirmations, ok := chaincommon.ConfirmationDepth(latestSlot, txSlot)
+		if !ok {
+			// Cross-RPC height skew: the endpoint that served the transaction is
+			// ahead of the one that served the latest slot. Defer rather than
+			// trust a wrapped depth; a later poll with a consistent view resolves it.
+			ec.logger.Warn().
+				Str("event_id", event.EventID).
+				Uint64("latest_slot", latestSlot).
+				Uint64("tx_slot", txSlot).
+				Msg("latest slot behind tx slot (RPC height skew); deferring confirmation")
+			continue
+		}
 
 		if confirmations >= requiredConfirmations {
 			// GasFeeUsed for outbound events is already set by the event parser from the on-chain event data
@@ -225,24 +236,17 @@ func (ec *EventConfirmer) getTxSignatureFromEventID(eventID string) string {
 	return parts[0]
 }
 
-// getRequiredConfirmations returns the required number of confirmations based on confirmation type
+// getRequiredConfirmations returns the required number of confirmations based on
+// confirmation type. The values are already resolved by the client's
+// applyDefaults (registry value, or a safe fallback when the registry is 0 and
+// zero-confirmation mode is not enabled), so a 0 here is an intentional instant
+// route and is honored as-is.
 func (ec *EventConfirmer) getRequiredConfirmations(confirmationType string) uint64 {
 	switch confirmationType {
 	case store.ConfirmationFast:
-		if ec.fastConfirmations > 0 {
-			return ec.fastConfirmations
-		}
-		return 5
-	case store.ConfirmationStandard:
-		if ec.standardConfirmations > 0 {
-			return ec.standardConfirmations
-		}
-		return 12
+		return ec.fastConfirmations
 	default:
-		// Default to standard if unknown
-		if ec.standardConfirmations > 0 {
-			return ec.standardConfirmations
-		}
-		return 12
+		// Standard and unknown types both use the standard depth.
+		return ec.standardConfirmations
 	}
 }
diff --git a/universalClient/chains/svm/event_confirmer_test.go b/universalClient/chains/svm/event_confirmer_test.go
index 10f9f7979..5048db818 100644
--- a/universalClient/chains/svm/event_confirmer_test.go
+++ b/universalClient/chains/svm/event_confirmer_test.go
@@ -129,10 +129,12 @@ func TestEventConfirmerGetRequiredConfirmations(t *testing.T) {
 		assert.Equal(t, uint64(5), confirmations)
 	})
 
-	t.Run("FAST confirmation type with zero uses default", func(t *testing.T) {
+	t.Run("FAST confirmation type with zero honored as instant", func(t *testing.T) {
+		// Fallback policy lives in the client's applyDefaults; the confirmer
+		// honors a resolved 0 as an instant route. See F-2026-18139.
 		confirmer := NewEventConfirmer(nil, nil, "solana:mainnet", 5, 0, 12, logger)
 		confirmations := confirmer.getRequiredConfirmations(store.ConfirmationFast)
-		assert.Equal(t, uint64(5), confirmations) // Default is 5
+		assert.Equal(t, uint64(0), confirmations)
 	})
 
 	t.Run("STANDARD confirmation type with custom value", func(t *testing.T) {
@@ -141,10 +143,10 @@ func TestEventConfirmerGetRequiredConfirmations(t *testing.T) {
 		assert.Equal(t, uint64(20), confirmations)
 	})
 
-	t.Run("STANDARD confirmation type with zero uses default", func(t *testing.T) {
+	t.Run("STANDARD confirmation type with zero honored as instant", func(t *testing.T) {
 		confirmer := NewEventConfirmer(nil, nil, "solana:mainnet", 5, 5, 0, logger)
 		confirmations := confirmer.getRequiredConfirmations(store.ConfirmationStandard)
-		assert.Equal(t, uint64(12), confirmations) // Default is 12
+		assert.Equal(t, uint64(0), confirmations)
 	})
 
 	t.Run("unknown type defaults to standard configured", func(t *testing.T) {
@@ -153,10 +155,10 @@ func TestEventConfirmerGetRequiredConfirmations(t *testing.T) {
 		assert.Equal(t, uint64(25), confirmations)
 	})
 
-	t.Run("unknown type with zero falls back to default 12", func(t *testing.T) {
+	t.Run("unknown type with zero standard honored as instant", func(t *testing.T) {
 		confirmer := NewEventConfirmer(nil, nil, "solana:mainnet", 5, 0, 0, logger)
 		confirmations := confirmer.getRequiredConfirmations("UNKNOWN")
-		assert.Equal(t, uint64(12), confirmations)
+		assert.Equal(t, uint64(0), confirmations)
 	})
 
 	t.Run("empty type defaults to standard", func(t *testing.T) {
@@ -326,16 +328,18 @@ func TestEventConfirmerGetRequiredConfirmations_MoreEdgeCases(t *testing.T) {
 		assert.Equal(t, uint64(10), unknown)
 	})
 
-	t.Run("zero fast falls back to default 5", func(t *testing.T) {
+	t.Run("zero fast honored as instant", func(t *testing.T) {
+		// Fallback policy lives in applyDefaults; the confirmer honors a
+		// resolved 0 as an instant route. See F-2026-18139.
 		ec := NewEventConfirmer(nil, nil, "solana:mainnet", 5, 0, 20, logger)
 		result := ec.getRequiredConfirmations(store.ConfirmationFast)
-		assert.Equal(t, uint64(5), result) // default 5
+		assert.Equal(t, uint64(0), result)
 	})
 
-	t.Run("zero standard falls back to default 12", func(t *testing.T) {
+	t.Run("zero standard honored as instant", func(t *testing.T) {
 		ec := NewEventConfirmer(nil, nil, "solana:mainnet", 5, 10, 0, logger)
 		result := ec.getRequiredConfirmations(store.ConfirmationStandard)
-		assert.Equal(t, uint64(12), result) // default 12
+		assert.Equal(t, uint64(0), result)
 	})
 }
 
diff --git a/universalClient/chains/svm/rpc_client.go b/universalClient/chains/svm/rpc_client.go
index fb788b7a8..ab257fadd 100644
--- a/universalClient/chains/svm/rpc_client.go
+++ b/universalClient/chains/svm/rpc_client.go
@@ -321,6 +321,7 @@ func (rc *RPCClient) GetTransaction(ctx context.Context, signature solana.Signat
 			signature,
 			&rpc.GetTransactionOpts{
 				Encoding:                       solana.EncodingBase64,
+				Commitment:                     rpc.CommitmentFinalized,
 				MaxSupportedTransactionVersion: &maxVersion,
 			},
 		)
diff --git a/universalClient/config/config_test.go b/universalClient/config/config_test.go
index 1efc379da..8a46e5b37 100644
--- a/universalClient/config/config_test.go
+++ b/universalClient/config/config_test.go
@@ -321,3 +321,28 @@ func TestGetChainCleanupSettings(t *testing.T) {
 		assert.Contains(t, err.Error(), "cleanup_interval_seconds")
 	})
 }
+
+// Regression for F-2026-18139: network gating must fail safe. Any value other
+// than "testnet" (including unset) is mainnet, and only testnet unlocks
+// zero-confirmation instant routes.
+func TestNetworkGating(t *testing.T) {
+	cases := []struct {
+		network      string
+		wantTestnet  bool
+	}{
+		{"", false},
+		{"mainnet", false},
+		{"MAINNET", false},
+		{"prod", false},
+		{"testnet", true},
+		{"TESTNET", true},
+		{"  testnet  ", true},
+	}
+	for _, tc := range cases {
+		t.Run("network="+tc.network, func(t *testing.T) {
+			c := &Config{Network: tc.network}
+			assert.Equal(t, tc.wantTestnet, c.IsTestnet())
+			assert.Equal(t, tc.wantTestnet, c.AllowsZeroConfirmations())
+		})
+	}
+}
diff --git a/universalClient/config/default_config.json b/universalClient/config/default_config.json
index 4355eace5..64d54e2ff 100644
--- a/universalClient/config/default_config.json
+++ b/universalClient/config/default_config.json
@@ -2,6 +2,7 @@
   "log_level": 1,
   "log_format": "console",
   "log_sampler": false,
+  "network": "mainnet",
   "push_chain_id": "localchain_9000-1",
   "push_chain_grpc_urls": [
     "localhost:9090"
diff --git a/universalClient/config/types.go b/universalClient/config/types.go
index 8a43a7091..7f8479848 100644
--- a/universalClient/config/types.go
+++ b/universalClient/config/types.go
@@ -1,6 +1,9 @@
 package config
 
-import "fmt"
+import (
+	"fmt"
+	"strings"
+)
 
 // KeyringBackend represents the type of keyring backend to use.
 type KeyringBackend string
@@ -10,6 +13,24 @@ const (
 	KeyringBackendFile KeyringBackend = "file"
 )
 
+// NetworkTestnet is the Network value that unlocks testnet-only relaxed behavior.
+const NetworkTestnet = "testnet"
+
+// IsTestnet reports whether this node is configured for testnet. Any value other
+// than "testnet" (including unset) is treated as mainnet so relaxed behaviors
+// fail safe. See [Config.AllowsZeroConfirmations].
+func (c *Config) IsTestnet() bool {
+	return strings.EqualFold(strings.TrimSpace(c.Network), NetworkTestnet)
+}
+
+// AllowsZeroConfirmations reports whether zero-confirmation ("instant") inbound
+// routes are permitted. Only testnet may honor a registry-configured
+// confirmation depth of 0; on mainnet a 0 falls back to a safe depth so inbounds
+// cannot finalize at their inclusion block. See F-2026-18139.
+func (c *Config) AllowsZeroConfirmations() bool {
+	return c.IsTestnet()
+}
+
 // Config holds all configuration for the Universal Validator.
 type Config struct {
 	// Logging
@@ -27,6 +48,12 @@ type Config struct {
 	ConfigRefreshIntervalSeconds int      `json:"config_refresh_interval_seconds"`
 	MaxRetries                   int      `json:"max_retries"`
 
+	// Network identifies the deployment network: "mainnet" or "testnet".
+	// Unset/unknown is treated as mainnet, the safe default. Testnet unlocks
+	// relaxed behaviors that must never apply to mainnet — currently
+	// zero-confirmation ("instant") inbound routes. See F-2026-18139.
+	Network string `json:"network"`
+
 	// Query Server
 	QueryServerPort int `json:"query_server_port"`
 

From 64aefe3df5f0dbd2bd54c714c42f773494894f5b Mon Sep 17 00:00:00 2001
From: aman035 <guptaaman200115@gmail.com>
Date: Wed, 12 Aug 2026 16:20:43 +0530
Subject: [PATCH 2/4] chore: rename Network to PushNetwork, trim comments
 (F-2026-18139)

---
 universalClient/chains/common/confirmation.go | 16 ++++----------
 universalClient/chains/evm/client.go          |  6 ++----
 universalClient/chains/evm/client_test.go     |  6 ++----
 universalClient/chains/evm/event_confirmer.go | 12 +++--------
 .../chains/evm/event_confirmer_test.go        |  6 ++----
 universalClient/chains/svm/client.go          |  6 ++----
 universalClient/chains/svm/client_test.go     |  6 ++----
 universalClient/chains/svm/event_confirmer.go | 12 +++--------
 .../chains/svm/event_confirmer_test.go        |  5 +----
 universalClient/config/config_test.go         |  9 +++-----
 universalClient/config/default_config.json    |  2 +-
 universalClient/config/types.go               | 21 +++++++------------
 12 files changed, 32 insertions(+), 75 deletions(-)

diff --git a/universalClient/chains/common/confirmation.go b/universalClient/chains/common/confirmation.go
index 0ba4e8437..6b2097d0f 100644
--- a/universalClient/chains/common/confirmation.go
+++ b/universalClient/chains/common/confirmation.go
@@ -1,17 +1,9 @@
 package common
 
-// ConfirmationDepth returns the number of confirmations for a transaction
-// observed at txHeight against a chain tip at latestHeight, defined as
-// latestHeight - txHeight + 1 (the inclusion block counts as one confirmation).
-//
-// ok is false when latestHeight < txHeight. That ordering is not physically
-// possible on a single consistent view of a chain, but the latest-height and
-// transaction reads are independent RPC calls that the pool round-robins across
-// endpoints. When the endpoint serving the transaction is ahead of the one
-// serving the tip, an unchecked latestHeight - txHeight underflows uint64 to a
-// value near 2^64 and satisfies any confirmation threshold, prematurely
-// finalizing an inbound. Callers must treat ok == false as "defer, still
-// pending" rather than trusting the returned depth.
+// ConfirmationDepth returns latestHeight - txHeight + 1, the confirmation count
+// with the inclusion block counted as one. ok is false when latestHeight <
+// txHeight (a cross-RPC height skew); callers must defer rather than trust the
+// depth, since the unchecked subtraction would underflow.
 func ConfirmationDepth(latestHeight, txHeight uint64) (depth uint64, ok bool) {
 	if latestHeight < txHeight {
 		return 0, false
diff --git a/universalClient/chains/evm/client.go b/universalClient/chains/evm/client.go
index bf3a9aab6..ed436f648 100644
--- a/universalClient/chains/evm/client.go
+++ b/universalClient/chains/evm/client.go
@@ -384,10 +384,8 @@ func (c *Client) applyDefaults() componentConfig {
 		config.standardConfirmations = uint64(c.registryConfig.BlockConfirmation.StandardInbound)
 	}
 
-	// A registry-configured 0 disables the reorg-safety depth (confirm at the
-	// inclusion block). Honor it only when zero-confirmation mode is explicitly
-	// enabled (testnet instant routes); otherwise fall back to a safe default so
-	// mainnet cannot silently finalize inbounds prematurely. See F-2026-18139.
+	// A registry-configured 0 disables the reorg-safety depth. Honor it only
+	// when instant routes are enabled; otherwise fall back to a safe default.
 	if !c.allowZeroConfirmations {
 		if config.fastConfirmations == 0 {
 			config.fastConfirmations = 2
diff --git a/universalClient/chains/evm/client_test.go b/universalClient/chains/evm/client_test.go
index 31ef5cabe..03195722d 100644
--- a/universalClient/chains/evm/client_test.go
+++ b/universalClient/chains/evm/client_test.go
@@ -431,10 +431,8 @@ func TestApplyDefaults(t *testing.T) {
 	})
 }
 
-// TestApplyDefaults_ZeroConfirmations covers the zero-confirmation policy from
-// F-2026-18139: a registry-configured 0 must fall back to a safe depth on
-// mainnet (allowZeroConfirmations=false) and be honored as an instant route
-// only on testnet (allowZeroConfirmations=true).
+// A registry-configured 0 falls back to a safe depth unless instant routes are
+// enabled, in which case it is honored.
 func TestApplyDefaults_ZeroConfirmations(t *testing.T) {
 	logger := zerolog.New(zerolog.NewTestWriter(t))
 
diff --git a/universalClient/chains/evm/event_confirmer.go b/universalClient/chains/evm/event_confirmer.go
index df72289f7..89a6f35e5 100644
--- a/universalClient/chains/evm/event_confirmer.go
+++ b/universalClient/chains/evm/event_confirmer.go
@@ -163,9 +163,7 @@ func (ec *EventConfirmer) processPendingEvents(ctx context.Context) error {
 		txBlock := receipt.BlockNumber.Uint64()
 		confirmations, ok := chaincommon.ConfirmationDepth(latestBlock, txBlock)
 		if !ok {
-			// Cross-RPC height skew: the endpoint that served the receipt is
-			// ahead of the one that served the latest block. Defer rather than
-			// trust a wrapped depth; a later poll with a consistent view resolves it.
+			// RPC height skew: latest block is behind the tx block. Defer.
 			ec.logger.Warn().
 				Str("event_id", event.EventID).
 				Uint64("latest_block", latestBlock).
@@ -257,17 +255,13 @@ func (ec *EventConfirmer) getTxHashFromEventID(eventID string) string {
 	return parts[0]
 }
 
-// getRequiredConfirmations returns the required number of confirmations based on
-// confirmation type. The values are already resolved by the client's
-// applyDefaults (registry value, or a safe fallback when the registry is 0 and
-// zero-confirmation mode is not enabled), so a 0 here is an intentional instant
-// route and is honored as-is.
+// getRequiredConfirmations returns the depth for a confirmation type. Values are
+// resolved by applyDefaults, so a 0 here is an intentional instant route.
 func (ec *EventConfirmer) getRequiredConfirmations(confirmationType string) uint64 {
 	switch confirmationType {
 	case store.ConfirmationFast:
 		return ec.fastConfirmations
 	default:
-		// Standard and unknown types both use the standard depth.
 		return ec.standardConfirmations
 	}
 }
diff --git a/universalClient/chains/evm/event_confirmer_test.go b/universalClient/chains/evm/event_confirmer_test.go
index d1f331067..f54f98163 100644
--- a/universalClient/chains/evm/event_confirmer_test.go
+++ b/universalClient/chains/evm/event_confirmer_test.go
@@ -375,10 +375,8 @@ func TestEventConfirmer_PendingEventsWithBlockHeightZero(t *testing.T) {
 	assert.Equal(t, uint64(0), pending[0].BlockHeight)
 }
 
-// The confirmer honors whatever depth it is given: the safe-fallback vs
-// zero-confirmation policy is resolved upstream in the client's applyDefaults
-// (see TestApplyDefaults_ZeroConfirmations). A 0 here is an intentional instant
-// route. Regression for F-2026-18139.
+// The confirmer honors whatever depth it is given; the fallback policy lives in
+// applyDefaults, so a 0 here is an intentional instant route.
 func TestEventConfirmer_GetRequiredConfirmations_ZeroValues(t *testing.T) {
 	logger := zerolog.Nop()
 
diff --git a/universalClient/chains/svm/client.go b/universalClient/chains/svm/client.go
index e198cdd4e..dd811c700 100644
--- a/universalClient/chains/svm/client.go
+++ b/universalClient/chains/svm/client.go
@@ -411,10 +411,8 @@ func (c *Client) applyDefaults() componentConfig {
 		config.standardConfirmations = uint64(c.registryConfig.BlockConfirmation.StandardInbound)
 	}
 
-	// A registry-configured 0 disables the reorg-safety depth (confirm at the
-	// inclusion slot). Honor it only when zero-confirmation mode is explicitly
-	// enabled (testnet instant routes); otherwise fall back to a safe default so
-	// mainnet cannot silently finalize inbounds prematurely. See F-2026-18139.
+	// A registry-configured 0 disables the reorg-safety depth. Honor it only
+	// when instant routes are enabled; otherwise fall back to a safe default.
 	if !c.allowZeroConfirmations {
 		if config.fastConfirmations == 0 {
 			config.fastConfirmations = 5
diff --git a/universalClient/chains/svm/client_test.go b/universalClient/chains/svm/client_test.go
index 3a2f03a4a..36a5a91bf 100644
--- a/universalClient/chains/svm/client_test.go
+++ b/universalClient/chains/svm/client_test.go
@@ -315,10 +315,8 @@ func TestApplyDefaults_ZeroValueNotApplied(t *testing.T) {
 	assert.Equal(t, 0, defaults.gasPriceMarkupPercent) // 0 is the default too
 }
 
-// TestApplyDefaults_ZeroConfirmations covers the zero-confirmation policy from
-// F-2026-18139: a registry-configured 0 must fall back to a safe depth on
-// mainnet (allowZeroConfirmations=false) and be honored as an instant route
-// only on testnet (allowZeroConfirmations=true).
+// A registry-configured 0 falls back to a safe depth unless instant routes are
+// enabled, in which case it is honored.
 func TestApplyDefaults_ZeroConfirmations(t *testing.T) {
 	logger := zerolog.New(zerolog.NewTestWriter(t))
 
diff --git a/universalClient/chains/svm/event_confirmer.go b/universalClient/chains/svm/event_confirmer.go
index 131e774f1..b78650da1 100644
--- a/universalClient/chains/svm/event_confirmer.go
+++ b/universalClient/chains/svm/event_confirmer.go
@@ -182,9 +182,7 @@ func (ec *EventConfirmer) processPendingEvents(ctx context.Context) error {
 		requiredConfirmations := ec.getRequiredConfirmations(event.ConfirmationType)
 		confirmations, ok := chaincommon.ConfirmationDepth(latestSlot, txSlot)
 		if !ok {
-			// Cross-RPC height skew: the endpoint that served the transaction is
-			// ahead of the one that served the latest slot. Defer rather than
-			// trust a wrapped depth; a later poll with a consistent view resolves it.
+			// RPC height skew: latest slot is behind the tx slot. Defer.
 			ec.logger.Warn().
 				Str("event_id", event.EventID).
 				Uint64("latest_slot", latestSlot).
@@ -236,17 +234,13 @@ func (ec *EventConfirmer) getTxSignatureFromEventID(eventID string) string {
 	return parts[0]
 }
 
-// getRequiredConfirmations returns the required number of confirmations based on
-// confirmation type. The values are already resolved by the client's
-// applyDefaults (registry value, or a safe fallback when the registry is 0 and
-// zero-confirmation mode is not enabled), so a 0 here is an intentional instant
-// route and is honored as-is.
+// getRequiredConfirmations returns the depth for a confirmation type. Values are
+// resolved by applyDefaults, so a 0 here is an intentional instant route.
 func (ec *EventConfirmer) getRequiredConfirmations(confirmationType string) uint64 {
 	switch confirmationType {
 	case store.ConfirmationFast:
 		return ec.fastConfirmations
 	default:
-		// Standard and unknown types both use the standard depth.
 		return ec.standardConfirmations
 	}
 }
diff --git a/universalClient/chains/svm/event_confirmer_test.go b/universalClient/chains/svm/event_confirmer_test.go
index 5048db818..290b82811 100644
--- a/universalClient/chains/svm/event_confirmer_test.go
+++ b/universalClient/chains/svm/event_confirmer_test.go
@@ -130,8 +130,7 @@ func TestEventConfirmerGetRequiredConfirmations(t *testing.T) {
 	})
 
 	t.Run("FAST confirmation type with zero honored as instant", func(t *testing.T) {
-		// Fallback policy lives in the client's applyDefaults; the confirmer
-		// honors a resolved 0 as an instant route. See F-2026-18139.
+		// Fallback policy lives in applyDefaults; the confirmer honors a resolved 0.
 		confirmer := NewEventConfirmer(nil, nil, "solana:mainnet", 5, 0, 12, logger)
 		confirmations := confirmer.getRequiredConfirmations(store.ConfirmationFast)
 		assert.Equal(t, uint64(0), confirmations)
@@ -329,8 +328,6 @@ func TestEventConfirmerGetRequiredConfirmations_MoreEdgeCases(t *testing.T) {
 	})
 
 	t.Run("zero fast honored as instant", func(t *testing.T) {
-		// Fallback policy lives in applyDefaults; the confirmer honors a
-		// resolved 0 as an instant route. See F-2026-18139.
 		ec := NewEventConfirmer(nil, nil, "solana:mainnet", 5, 0, 20, logger)
 		result := ec.getRequiredConfirmations(store.ConfirmationFast)
 		assert.Equal(t, uint64(0), result)
diff --git a/universalClient/config/config_test.go b/universalClient/config/config_test.go
index 8a46e5b37..b656c5190 100644
--- a/universalClient/config/config_test.go
+++ b/universalClient/config/config_test.go
@@ -322,13 +322,10 @@ func TestGetChainCleanupSettings(t *testing.T) {
 	})
 }
 
-// Regression for F-2026-18139: network gating must fail safe. Any value other
-// than "testnet" (including unset) is mainnet, and only testnet unlocks
-// zero-confirmation instant routes.
 func TestNetworkGating(t *testing.T) {
 	cases := []struct {
-		network      string
-		wantTestnet  bool
+		network     string
+		wantTestnet bool
 	}{
 		{"", false},
 		{"mainnet", false},
@@ -340,7 +337,7 @@ func TestNetworkGating(t *testing.T) {
 	}
 	for _, tc := range cases {
 		t.Run("network="+tc.network, func(t *testing.T) {
-			c := &Config{Network: tc.network}
+			c := &Config{PushNetwork: tc.network}
 			assert.Equal(t, tc.wantTestnet, c.IsTestnet())
 			assert.Equal(t, tc.wantTestnet, c.AllowsZeroConfirmations())
 		})
diff --git a/universalClient/config/default_config.json b/universalClient/config/default_config.json
index 64d54e2ff..86867d20b 100644
--- a/universalClient/config/default_config.json
+++ b/universalClient/config/default_config.json
@@ -2,7 +2,7 @@
   "log_level": 1,
   "log_format": "console",
   "log_sampler": false,
-  "network": "mainnet",
+  "push_network": "mainnet",
   "push_chain_id": "localchain_9000-1",
   "push_chain_grpc_urls": [
     "localhost:9090"
diff --git a/universalClient/config/types.go b/universalClient/config/types.go
index 7f8479848..f35484dac 100644
--- a/universalClient/config/types.go
+++ b/universalClient/config/types.go
@@ -13,20 +13,16 @@ const (
 	KeyringBackendFile KeyringBackend = "file"
 )
 
-// NetworkTestnet is the Network value that unlocks testnet-only relaxed behavior.
 const NetworkTestnet = "testnet"
 
-// IsTestnet reports whether this node is configured for testnet. Any value other
-// than "testnet" (including unset) is treated as mainnet so relaxed behaviors
-// fail safe. See [Config.AllowsZeroConfirmations].
+// IsTestnet reports whether this node is on testnet. Any other value, including
+// unset, is treated as mainnet.
 func (c *Config) IsTestnet() bool {
-	return strings.EqualFold(strings.TrimSpace(c.Network), NetworkTestnet)
+	return strings.EqualFold(strings.TrimSpace(c.PushNetwork), NetworkTestnet)
 }
 
-// AllowsZeroConfirmations reports whether zero-confirmation ("instant") inbound
-// routes are permitted. Only testnet may honor a registry-configured
-// confirmation depth of 0; on mainnet a 0 falls back to a safe depth so inbounds
-// cannot finalize at their inclusion block. See F-2026-18139.
+// AllowsZeroConfirmations reports whether a registry confirmation depth of 0 is
+// honored (instant routes) instead of falling back to a safe depth.
 func (c *Config) AllowsZeroConfirmations() bool {
 	return c.IsTestnet()
 }
@@ -48,11 +44,8 @@ type Config struct {
 	ConfigRefreshIntervalSeconds int      `json:"config_refresh_interval_seconds"`
 	MaxRetries                   int      `json:"max_retries"`
 
-	// Network identifies the deployment network: "mainnet" or "testnet".
-	// Unset/unknown is treated as mainnet, the safe default. Testnet unlocks
-	// relaxed behaviors that must never apply to mainnet — currently
-	// zero-confirmation ("instant") inbound routes. See F-2026-18139.
-	Network string `json:"network"`
+	// PushNetwork is "mainnet" or "testnet"; unset/unknown is treated as mainnet.
+	PushNetwork string `json:"push_network"`
 
 	// Query Server
 	QueryServerPort int `json:"query_server_port"`

From 1bc56485dc63167f4992db285804b05e025a0e3f Mon Sep 17 00:00:00 2001
From: aman035 <guptaaman200115@gmail.com>
Date: Wed, 12 Aug 2026 16:32:35 +0530
Subject: [PATCH 3/4] refactor: extract default confirmation depths to common
 constants; EVM fast default 5 (F-2026-18139)

---
 universalClient/chains/common/confirmation.go | 7 +++++++
 universalClient/chains/evm/client.go          | 8 ++++----
 universalClient/chains/evm/client_test.go     | 8 ++++----
 universalClient/chains/svm/client.go          | 8 ++++----
 4 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/universalClient/chains/common/confirmation.go b/universalClient/chains/common/confirmation.go
index 6b2097d0f..438159197 100644
--- a/universalClient/chains/common/confirmation.go
+++ b/universalClient/chains/common/confirmation.go
@@ -1,5 +1,12 @@
 package common
 
+// Safe fallback confirmation depths used when the registry configures 0 and
+// instant routes are not enabled.
+const (
+	DefaultFastConfirmations     uint64 = 5
+	DefaultStandardConfirmations uint64 = 12
+)
+
 // ConfirmationDepth returns latestHeight - txHeight + 1, the confirmation count
 // with the inclusion block counted as one. ok is false when latestHeight <
 // txHeight (a cross-RPC height skew); callers must defer rather than trust the
diff --git a/universalClient/chains/evm/client.go b/universalClient/chains/evm/client.go
index ed436f648..1bce6ac66 100644
--- a/universalClient/chains/evm/client.go
+++ b/universalClient/chains/evm/client.go
@@ -359,8 +359,8 @@ func (c *Client) applyDefaults() componentConfig {
 	config := componentConfig{
 		eventPollingInterval:  5,  // default
 		gasPriceInterval:      30, // default
-		fastConfirmations:     2,
-		standardConfirmations: 12,
+		fastConfirmations:     common.DefaultFastConfirmations,
+		standardConfirmations: common.DefaultStandardConfirmations,
 	}
 
 	// Apply event polling interval
@@ -388,10 +388,10 @@ func (c *Client) applyDefaults() componentConfig {
 	// when instant routes are enabled; otherwise fall back to a safe default.
 	if !c.allowZeroConfirmations {
 		if config.fastConfirmations == 0 {
-			config.fastConfirmations = 2
+			config.fastConfirmations = common.DefaultFastConfirmations
 		}
 		if config.standardConfirmations == 0 {
-			config.standardConfirmations = 12
+			config.standardConfirmations = common.DefaultStandardConfirmations
 		}
 	}
 
diff --git a/universalClient/chains/evm/client_test.go b/universalClient/chains/evm/client_test.go
index 03195722d..9f05086fb 100644
--- a/universalClient/chains/evm/client_test.go
+++ b/universalClient/chains/evm/client_test.go
@@ -342,7 +342,7 @@ func TestApplyDefaults(t *testing.T) {
 		assert.Equal(t, 5, cfg.eventPollingInterval)
 		assert.Equal(t, 30, cfg.gasPriceInterval)
 		assert.Equal(t, 0, cfg.gasPriceMarkupPercent)
-		assert.Equal(t, uint64(2), cfg.fastConfirmations)
+		assert.Equal(t, uint64(5), cfg.fastConfirmations)
 		assert.Equal(t, uint64(12), cfg.standardConfirmations)
 	})
 
@@ -412,7 +412,7 @@ func TestApplyDefaults(t *testing.T) {
 		}
 
 		cfg := client.applyDefaults()
-		assert.Equal(t, uint64(2), cfg.fastConfirmations)
+		assert.Equal(t, uint64(5), cfg.fastConfirmations)
 		assert.Equal(t, uint64(12), cfg.standardConfirmations)
 	})
 
@@ -426,7 +426,7 @@ func TestApplyDefaults(t *testing.T) {
 		}
 
 		cfg := client.applyDefaults()
-		assert.Equal(t, uint64(2), cfg.fastConfirmations)
+		assert.Equal(t, uint64(5), cfg.fastConfirmations)
 		assert.Equal(t, uint64(12), cfg.standardConfirmations)
 	})
 }
@@ -452,7 +452,7 @@ func TestApplyDefaults_ZeroConfirmations(t *testing.T) {
 		}
 
 		cfg := client.applyDefaults()
-		assert.Equal(t, uint64(2), cfg.fastConfirmations, "zero fast must not disable depth on mainnet")
+		assert.Equal(t, uint64(5), cfg.fastConfirmations, "zero fast must not disable depth on mainnet")
 		assert.Equal(t, uint64(12), cfg.standardConfirmations, "zero standard must not disable depth on mainnet")
 	})
 
diff --git a/universalClient/chains/svm/client.go b/universalClient/chains/svm/client.go
index dd811c700..e63af21df 100644
--- a/universalClient/chains/svm/client.go
+++ b/universalClient/chains/svm/client.go
@@ -368,8 +368,8 @@ func (c *Client) applyDefaults() componentConfig {
 	config := componentConfig{
 		eventPollingInterval:     5,  // default
 		gasPriceInterval:         30, // default
-		fastConfirmations:        5,  // Solana fast confirmations
-		standardConfirmations:    12, // Solana standard confirmations
+		fastConfirmations:        common.DefaultFastConfirmations,
+		standardConfirmations:    common.DefaultStandardConfirmations,
 		rentReclaimSweepInterval: rentReclaimSweepInterval,
 		rentReclaimMinPDAAge:     rentReclaimMinPDAAge,
 	}
@@ -415,10 +415,10 @@ func (c *Client) applyDefaults() componentConfig {
 	// when instant routes are enabled; otherwise fall back to a safe default.
 	if !c.allowZeroConfirmations {
 		if config.fastConfirmations == 0 {
-			config.fastConfirmations = 5
+			config.fastConfirmations = common.DefaultFastConfirmations
 		}
 		if config.standardConfirmations == 0 {
-			config.standardConfirmations = 12
+			config.standardConfirmations = common.DefaultStandardConfirmations
 		}
 	}
 

From d68bde5627820e26e72f82bd1c67755b6363cf64 Mon Sep 17 00:00:00 2001
From: aman035 <guptaaman200115@gmail.com>
Date: Wed, 12 Aug 2026 17:19:31 +0530
Subject: [PATCH 4/4] chore: log RPC height skew at debug not warn
 (F-2026-18139)

---
 universalClient/chains/evm/event_confirmer.go | 2 +-
 universalClient/chains/svm/event_confirmer.go | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/universalClient/chains/evm/event_confirmer.go b/universalClient/chains/evm/event_confirmer.go
index 89a6f35e5..79a6b93d6 100644
--- a/universalClient/chains/evm/event_confirmer.go
+++ b/universalClient/chains/evm/event_confirmer.go
@@ -164,7 +164,7 @@ func (ec *EventConfirmer) processPendingEvents(ctx context.Context) error {
 		confirmations, ok := chaincommon.ConfirmationDepth(latestBlock, txBlock)
 		if !ok {
 			// RPC height skew: latest block is behind the tx block. Defer.
-			ec.logger.Warn().
+			ec.logger.Debug().
 				Str("event_id", event.EventID).
 				Uint64("latest_block", latestBlock).
 				Uint64("tx_block", txBlock).
diff --git a/universalClient/chains/svm/event_confirmer.go b/universalClient/chains/svm/event_confirmer.go
index b78650da1..acb3f29bd 100644
--- a/universalClient/chains/svm/event_confirmer.go
+++ b/universalClient/chains/svm/event_confirmer.go
@@ -183,7 +183,7 @@ func (ec *EventConfirmer) processPendingEvents(ctx context.Context) error {
 		confirmations, ok := chaincommon.ConfirmationDepth(latestSlot, txSlot)
 		if !ok {
 			// RPC height skew: latest slot is behind the tx slot. Defer.
-			ec.logger.Warn().
+			ec.logger.Debug().
 				Str("event_id", event.EventID).
 				Uint64("latest_slot", latestSlot).
 				Uint64("tx_slot", txSlot).