diff --git a/packages/ui-extensions-server-kit/src/ExtensionServerClient/ExtensionServerClient.test.ts b/packages/ui-extensions-server-kit/src/ExtensionServerClient/ExtensionServerClient.test.ts
index 8ef4ffa1aea..9258905db26 100644
--- a/packages/ui-extensions-server-kit/src/ExtensionServerClient/ExtensionServerClient.test.ts
+++ b/packages/ui-extensions-server-kit/src/ExtensionServerClient/ExtensionServerClient.test.ts
@@ -163,6 +163,12 @@ describe('ExtensionServerClient', () => {
   })
 
   describe('initialization', () => {
+    test('generates a random UUID as id', () => {
+      const client = new ExtensionServerClient(defaultOptions)
+      const uuidRegex = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i
+      expect(client.id).toMatch(uuidRegex)
+    })
+
     test('connects to the target websocket', async () => {
       // Create client
       const client = new ExtensionServerClient(defaultOptions)
diff --git a/packages/ui-extensions-server-kit/src/ExtensionServerClient/ExtensionServerClient.ts b/packages/ui-extensions-server-kit/src/ExtensionServerClient/ExtensionServerClient.ts
index 507bfb5df73..1484d115272 100644
--- a/packages/ui-extensions-server-kit/src/ExtensionServerClient/ExtensionServerClient.ts
+++ b/packages/ui-extensions-server-kit/src/ExtensionServerClient/ExtensionServerClient.ts
@@ -32,7 +32,8 @@ export class ExtensionServerClient implements ExtensionServer.Client {
   private uiExtensionsByUuid: Record<string, ExtensionServer.UIExtension> = {}
 
   constructor(options: DeepPartial<ExtensionServer.Options> = {}) {
-    this.id = (Math.random() + 1).toString(36).substring(7)
+    // Security: Use a cryptographically secure random UUID to prevent ID predictability
+    this.id = globalThis.crypto.randomUUID()
     this.options = getValidatedOptions({
       ...options,
       connection: {