diff --git a/.changeset/hardening-supply-chain.md b/.changeset/hardening-supply-chain.md
new file mode 100644
index 00000000..1eea4a3d
--- /dev/null
+++ b/.changeset/hardening-supply-chain.md
@@ -0,0 +1,22 @@
+---
+'@moonshot-ai/kimi-code': minor
+'@moonshot-ai/agent-core-v2': minor
+'@moonshot-ai/agent-core': minor
+---
+
+Tighten how code arrives on the machine.
+
+The plugin catalog now has to be served over https from an allowed host
+(`code.kimi.com` / `cdn.kimi.com` by default). The catalog picks which plugins
+are offered and where their archives come from, and an installed plugin can
+declare a spawnable `mcpServers` command, so whoever serves it effectively picks
+code that runs locally. A self-hosted catalog is still possible by naming its
+host in `KIMI_CODE_PLUGIN_MARKETPLACE_ALLOWED_HOSTS`.
+
+Remote plugin archives must likewise use https. Plaintext to loopback stays
+allowed for local dev and test servers, where there is no network path to
+tamper with.
+
+The native (`curl … install.sh | bash`) updater is no longer run unattended.
+Nothing verifies what the CDN returns, so the command is now surfaced for the
+user to run deliberately, matching what Windows already did.
diff --git a/apps/kimi-code/src/cli/update/preflight.ts b/apps/kimi-code/src/cli/update/preflight.ts
index 09889903..1e0b6c1e 100644
--- a/apps/kimi-code/src/cli/update/preflight.ts
+++ b/apps/kimi-code/src/cli/update/preflight.ts
@@ -87,7 +87,7 @@ export function installCommandFor(
   }
 }
 
-export function canAutoInstall(source: InstallSource, platform: NodeJS.Platform): boolean {
+export function canAutoInstall(source: InstallSource, _platform: NodeJS.Platform): boolean {
   switch (source) {
     case 'npm-global':
     case 'pnpm-global':
@@ -99,7 +99,11 @@ export function canAutoInstall(source: InstallSource, platform: NodeJS.Platform)
       // behind the CDN release — prompt the user to run `brew upgrade` manually.
       return false;
     case 'native':
-      return platform !== 'win32';
+      // The native updater is `curl … install.sh | bash` against the CDN,
+      // with nothing verifying what comes back. Running that unattended in
+      // the background turns a bad day at the CDN into local code execution,
+      // so surface the command and let the user run it deliberately.
+      return false;
     case 'unsupported':
       return false;
   }
diff --git a/apps/kimi-code/src/utils/plugin-marketplace.ts b/apps/kimi-code/src/utils/plugin-marketplace.ts
index 2ad4caa8..81dfe89a 100644
--- a/apps/kimi-code/src/utils/plugin-marketplace.ts
+++ b/apps/kimi-code/src/utils/plugin-marketplace.ts
@@ -182,12 +182,62 @@ export function parsePluginMarketplace(raw: string, location: MarketplaceLocatio
   };
 }
 
+/**
+ * Hosts the catalog may be fetched from over the network.
+ *
+ * The catalog decides which plugins are offered and where their archives come
+ * from, and an installed plugin can declare an `mcpServers` command that gets
+ * spawned — so whoever serves this file chooses code that runs on the machine.
+ * Anything beyond these hosts has to be named deliberately through
+ * `KIMI_CODE_PLUGIN_MARKETPLACE_ALLOWED_HOSTS` (comma-separated), which keeps a
+ * self-hosted internal catalog possible without leaving the default open.
+ */
+const DEFAULT_MARKETPLACE_HOSTS = ['code.kimi.com', 'cdn.kimi.com'];
+const MARKETPLACE_ALLOWED_HOSTS_ENV = 'KIMI_CODE_PLUGIN_MARKETPLACE_ALLOWED_HOSTS';
+
+function allowedMarketplaceHosts(env: NodeJS.ProcessEnv = process.env): readonly string[] {
+  const extra = (env[MARKETPLACE_ALLOWED_HOSTS_ENV] ?? '')
+    .split(',')
+    .map((host) => host.trim().toLowerCase())
+    .filter((host) => host.length > 0);
+  return [...DEFAULT_MARKETPLACE_HOSTS, ...extra];
+}
+
+const LOOPBACK_MARKETPLACE_HOSTS = new Set(['localhost', '127.0.0.1', '::1']);
+
+function assertAllowedMarketplaceUrl(raw: string): void {
+  let url: URL;
+  try {
+    url = new URL(raw);
+  } catch {
+    throw new Error(`Plugin marketplace URL is not a valid URL: ${raw}`);
+  }
+  // A catalog served from this machine has no network path to tamper with.
+  if (LOOPBACK_MARKETPLACE_HOSTS.has(url.hostname.toLowerCase())) return;
+  if (url.protocol !== 'https:') {
+    throw new Error(
+      `Plugin marketplace must be served over https (got "${url.protocol}//"). ` +
+        `The catalog selects code that will run locally, so it is not fetched over plaintext.`,
+    );
+  }
+  const host = url.hostname.toLowerCase();
+  const allowed = allowedMarketplaceHosts();
+  if (!allowed.includes(host)) {
+    throw new Error(
+      `Plugin marketplace host "${host}" is not allowed. ` +
+        `Allowed: ${allowed.join(', ')}. ` +
+        `Add it to ${MARKETPLACE_ALLOWED_HOSTS_ENV} to use a self-hosted catalog.`,
+    );
+  }
+}
+
 function resolveMarketplaceLocation(source: string, workDir: string): MarketplaceLocation {
   const trimmed = source.trim();
   if (trimmed.length === 0) {
     throw new Error(`${KIMI_CODE_PLUGIN_MARKETPLACE_URL_ENV} cannot be empty.`);
   }
   if (trimmed.startsWith('http://') || trimmed.startsWith('https://')) {
+    assertAllowedMarketplaceUrl(trimmed);
     return { raw: trimmed, kind: 'remote', resolved: trimmed };
   }
   if (trimmed.startsWith('file://')) {
diff --git a/apps/kimi-code/test/cli/update/preflight.test.ts b/apps/kimi-code/test/cli/update/preflight.test.ts
index 2f7439f5..4dcae7ca 100644
--- a/apps/kimi-code/test/cli/update/preflight.test.ts
+++ b/apps/kimi-code/test/cli/update/preflight.test.ts
@@ -491,28 +491,21 @@ describe('runUpdatePreflight', () => {
     expect(mocks.spawn).not.toHaveBeenCalled();
   });
 
-  it('native on darwin: spawns bash -c with pipefail-guarded curl|bash', async () => {
+  it('native on darwin: prints the manual install command, does not spawn', async () => {
+    // The native updater is an unverified `curl … | bash` against the CDN, so
+    // it is never run unattended: the command is surfaced for the user to run.
     disableAutoInstall();
     mocks.readUpdateCache.mockResolvedValue(cacheWith('0.5.0'));
     mocks.refreshUpdateCache.mockResolvedValue(cacheWith('0.5.0'));
     mocks.detectInstallSource.mockResolvedValue('native');
-    mocks.promptForInstallChoice.mockResolvedValue('install');
-    mockSpawnExit(0);
     const originalPlatform = process.platform;
     Object.defineProperty(process, 'platform', { value: 'darwin' });
     try {
-      const { options } = captureOutput();
-      await runUpdatePreflight('0.4.0', options);
-      const call = mocks.spawn.mock.calls[0];
-      expect(call?.[0]).toBe('bash');
-      expect(call?.[2]).toEqual({ stdio: 'inherit' });
-      const [flag, script] = call?.[1] as string[];
-      expect(flag).toBe('-c');
-      // pipefail must come before the pipeline so a failed `curl` is not masked
-      // by the trailing `bash` exiting 0 (see "surfaces a failed curl" below).
-      expect(script).toContain('set -o pipefail');
-      expect(script).toContain('curl -fsSL https://code.kimi.com/kimi-code/install.sh');
-      expect(script).toContain('| bash');
+      const { stdout, options } = captureOutput();
+      await expect(runUpdatePreflight('0.4.0', options)).resolves.toBe('continue');
+      expect(stdout.join('')).toContain('curl -fsSL https://code.kimi.com/kimi-code/install.sh');
+      expect(promptForInstallChoice).not.toHaveBeenCalled();
+      expect(mocks.spawn).not.toHaveBeenCalled();
     } finally {
       Object.defineProperty(process, 'platform', { value: originalPlatform });
     }
diff --git a/apps/kimi-code/test/tui/kimi-tui-message-flow.test.ts b/apps/kimi-code/test/tui/kimi-tui-message-flow.test.ts
index acd25f34..4a178f8a 100644
--- a/apps/kimi-code/test/tui/kimi-tui-message-flow.test.ts
+++ b/apps/kimi-code/test/tui/kimi-tui-message-flow.test.ts
@@ -5638,6 +5638,9 @@ command = "vim"
   it('shows an inline Official error when the marketplace is unreachable, keeping the panel open', async () => {
     const originalFetch = globalThis.fetch;
     process.env['KIMI_CODE_PLUGIN_MARKETPLACE_URL'] = 'https://example.test/marketplace.json';
+    // Allow the host so this stays a test about an unreachable catalog rather
+    // than one rejected by the host allowlist.
+    process.env['KIMI_CODE_PLUGIN_MARKETPLACE_ALLOWED_HOSTS'] = 'example.test';
     vi.stubGlobal(
       'fetch',
       vi.fn(async () => {
@@ -5665,6 +5668,7 @@ command = "vim"
       // The panel stays mounted; the failure does not close /plugins.
       expect(driver.state.editorContainer.children[0]).toBe(panel);
     } finally {
+      delete process.env['KIMI_CODE_PLUGIN_MARKETPLACE_ALLOWED_HOSTS'];
       vi.stubGlobal('fetch', originalFetch);
     }
   });
diff --git a/apps/kimi-code/test/utils/plugin-marketplace.test.ts b/apps/kimi-code/test/utils/plugin-marketplace.test.ts
index 5bc803ec..413357fa 100644
--- a/apps/kimi-code/test/utils/plugin-marketplace.test.ts
+++ b/apps/kimi-code/test/utils/plugin-marketplace.test.ts
@@ -305,6 +305,9 @@ describe('loadPluginMarketplace', () => {
   });
 
   it('keeps the built-in entries when the catalog is unreachable', async () => {
+    // Not a default catalog host; name it explicitly the way an operator
+    // would for a self-hosted catalog.
+    vi.stubEnv('KIMI_CODE_PLUGIN_MARKETPLACE_ALLOWED_HOSTS', 'example.test,example.com');
     const fetchImpl = vi.fn(async () => {
       throw new Error('fetch failed');
     }) as unknown as typeof fetch;
@@ -524,6 +527,7 @@ describe('loadPluginMarketplace', () => {
   });
 
   it('loads an explicit remote marketplace with injectable fetch', async () => {
+    vi.stubEnv('KIMI_CODE_PLUGIN_MARKETPLACE_ALLOWED_HOSTS', 'example.com');
     const source = 'https://example.com/plugins/marketplace.json';
     const fetchImpl = vi.fn(async () => ({
       ok: true,
@@ -588,4 +592,49 @@ describe('loadPluginMarketplace', () => {
     );
   });
 
+
 });
+
+describe('marketplace host policy', () => {
+  it('rejects a plaintext http catalog', async () => {
+    await expect(
+      loadPluginMarketplace({ workDir: '/tmp', source: 'http://evil.example/marketplace.json' }),
+    ).rejects.toThrow(/must be served over https/);
+  });
+
+  it('rejects an https catalog on a host that is not allowed', async () => {
+    await expect(
+      loadPluginMarketplace({ workDir: '/tmp', source: 'https://evil.example/marketplace.json' }),
+    ).rejects.toThrow(/is not allowed/);
+  });
+
+  it('allows a self-hosted catalog named in the allowlist env', async () => {
+    vi.stubEnv('KIMI_CODE_PLUGIN_MARKETPLACE_ALLOWED_HOSTS', 'internal.example');
+    const fetchImpl = vi.fn(async () =>
+      new Response(JSON.stringify({ plugins: [] }), { status: 200 }),
+    ) as unknown as typeof fetch;
+
+    await expect(
+      loadPluginMarketplace({
+        workDir: '/tmp',
+        source: 'https://internal.example/marketplace.json',
+        fetchImpl,
+      }),
+    ).resolves.toMatchObject({ plugins: [] });
+  });
+
+  it('allows a loopback catalog over http (local dev server)', async () => {
+    const fetchImpl = vi.fn(async () =>
+      new Response(JSON.stringify({ plugins: [] }), { status: 200 }),
+    ) as unknown as typeof fetch;
+
+    await expect(
+      loadPluginMarketplace({
+        workDir: '/tmp',
+        source: 'http://127.0.0.1:8787/marketplace.json',
+        fetchImpl,
+      }),
+    ).resolves.toMatchObject({ plugins: [] });
+  });
+});
+
diff --git a/packages/agent-core-v2/src/app/plugin/source.ts b/packages/agent-core-v2/src/app/plugin/source.ts
index 7909e81a..e8cdd4d7 100644
--- a/packages/agent-core-v2/src/app/plugin/source.ts
+++ b/packages/agent-core-v2/src/app/plugin/source.ts
@@ -16,13 +16,39 @@ export type InstallSource = ResolvedSource;
 
 const SHA_RE = /^[0-9a-f]{7,40}$/;
 
+const LOOPBACK_HOSTS = new Set(['localhost', '127.0.0.1', '::1', '[::1]']);
+
+/**
+ * Plaintext to the local machine has no network path to tamper with, so it
+ * stays allowed (local test servers, `pnpm dev:plugin-marketplace`). Plaintext
+ * to anything else does not.
+ */
+function isLoopbackUrl(raw: string): boolean {
+  try {
+    return LOOPBACK_HOSTS.has(new URL(raw).hostname.toLowerCase());
+  } catch {
+    return false;
+  }
+}
+
+
 export function resolveInstallSource(source: string): ResolvedSource {
   const trimmed = source.trim();
 
   const github = parseGithubUrl(trimmed);
   if (github !== undefined) return github;
 
-  if (trimmed.startsWith('http://') || trimmed.startsWith('https://')) {
+  if (trimmed.startsWith('http://') && !isLoopbackUrl(trimmed)) {
+    // A plugin archive is executable content: it can ship an mcpServers
+    // command that gets spawned. Over plaintext there is nothing binding the
+    // bytes to the publisher, so refuse rather than trust the network.
+    throw new Error2(
+      ErrorCodes.VALIDATION_FAILED,
+      `Plugin source must use https (got "${trimmed}")`,
+      { details: { source } },
+    );
+  }
+  if (trimmed.startsWith('https://') || trimmed.startsWith('http://')) {
     return { kind: 'zip-url', path: trimmed };
   }
   if (!path.isAbsolute(trimmed)) {
diff --git a/packages/agent-core/src/plugin/source.ts b/packages/agent-core/src/plugin/source.ts
index 38a02ece..5f8e76d0 100644
--- a/packages/agent-core/src/plugin/source.ts
+++ b/packages/agent-core/src/plugin/source.ts
@@ -15,13 +15,35 @@ export type InstallSource = ResolvedSource;
 
 const SHA_RE = /^[0-9a-f]{7,40}$/;
 
+const LOOPBACK_HOSTS = new Set(['localhost', '127.0.0.1', '::1', '[::1]']);
+
+/**
+ * Plaintext to the local machine has no network path to tamper with, so it
+ * stays allowed (local test servers, `pnpm dev:plugin-marketplace`). Plaintext
+ * to anything else does not.
+ */
+function isLoopbackUrl(raw: string): boolean {
+  try {
+    return LOOPBACK_HOSTS.has(new URL(raw).hostname.toLowerCase());
+  } catch {
+    return false;
+  }
+}
+
+
 export function resolveInstallSource(source: string): ResolvedSource {
   const trimmed = source.trim();
 
   const github = parseGithubUrl(trimmed);
   if (github !== undefined) return github;
 
-  if (trimmed.startsWith('http://') || trimmed.startsWith('https://')) {
+  if (trimmed.startsWith('http://') && !isLoopbackUrl(trimmed)) {
+    // A plugin archive is executable content: it can ship an mcpServers
+    // command that gets spawned. Over plaintext there is nothing binding the
+    // bytes to the publisher, so refuse rather than trust the network.
+    throw new Error(`Plugin source must use https (got "${source}")`);
+  }
+  if (trimmed.startsWith('https://') || trimmed.startsWith('http://')) {
     return { kind: 'zip-url', path: trimmed };
   }
   if (!path.isAbsolute(trimmed)) {
diff --git a/packages/agent-core/test/plugin/source.test.ts b/packages/agent-core/test/plugin/source.test.ts
index 12b76bc4..f3981fa1 100644
--- a/packages/agent-core/test/plugin/source.test.ts
+++ b/packages/agent-core/test/plugin/source.test.ts
@@ -8,9 +8,15 @@ describe('resolveInstallSource', () => {
     expect(result).toEqual({ kind: 'zip-url', path: 'https://example.com/plugin.zip' });
   });
 
-  it('recognizes http:// as zip-url', () => {
-    const result = resolveInstallSource('http://example.com/plugin.zip');
-    expect(result).toEqual({ kind: 'zip-url', path: 'http://example.com/plugin.zip' });
+  it('rejects plaintext http:// for a remote plugin archive', () => {
+    // A plugin archive can ship a spawnable mcpServers command, so plaintext
+    // delivery from a remote host is refused.
+    expect(() => resolveInstallSource('http://example.com/plugin.zip')).toThrow(/must use https/);
+  });
+
+  it('still allows http:// to loopback (local test/dev servers)', () => {
+    const url = 'http://127.0.0.1:8080/plugin.zip';
+    expect(resolveInstallSource(url)).toEqual({ kind: 'zip-url', path: url });
   });
 
   it('recognizes absolute path as local-path', () => {
@@ -169,10 +175,9 @@ describe('resolveInstallSource', () => {
       expect(result).toEqual({ kind: 'zip-url', path: url });
     });
 
-    it('treats http:// (non-https) github URL as plain zip-url', () => {
+    it('rejects a http:// github URL rather than treating it as a zip-url', () => {
       const url = 'http://github.com/wbxl2000/superpowers';
-      const result = resolveInstallSource(url);
-      expect(result).toEqual({ kind: 'zip-url', path: url });
+      expect(() => resolveInstallSource(url)).toThrow(/must use https/);
     });
 
     it('percent-decodes %23 in /releases/tag/ so storage is human-readable', () => {