diff --git a/apps/server/src/adapters/WebsocketAdapter.ts b/apps/server/src/adapters/WebsocketAdapter.ts
index e786c2f03..008266c44 100644
--- a/apps/server/src/adapters/WebsocketAdapter.ts
+++ b/apps/server/src/adapters/WebsocketAdapter.ts
@@ -62,11 +62,22 @@ class SocketServer implements IAdapter {
     this.wss = new WebSocketServer({ path: `${prefix}/ws`, server, maxPayload: this.MAX_PAYLOAD });
 
     this.wss.on('connection', (ws, req) => {
+      // Rejected sockets can emit an error while their close handshake is in progress.
+      ws.on('error', console.error);
+
+      let isAuthenticated = false;
       authenticateSocket(ws, req, (error) => {
         if (error) {
           ws.close(1008, 'Unauthorized');
+          return;
         }
+        isAuthenticated = true;
       });
+
+      if (!isAuthenticated) {
+        return;
+      }
+
       const clientId = generateId();
       const clientName = getRandomName();
       function sendPacket<T extends MessageTag>(
@@ -94,8 +105,6 @@ class SocketServer implements IAdapter {
       // send store payload on connect
       sendPacket(MessageTag.RuntimeData, eventStore.poll());
 
-      ws.on('error', console.error);
-
       ws.on('close', () => {
         this.clients.delete(clientId);
         logger.info(LogOrigin.Client, `${this.clients.size} Connections with disconnected: ${clientName}`);
diff --git a/apps/server/src/adapters/__tests__/WebsocketAdapter.test.ts b/apps/server/src/adapters/__tests__/WebsocketAdapter.test.ts
new file mode 100644
index 000000000..0b0d080d1
--- /dev/null
+++ b/apps/server/src/adapters/__tests__/WebsocketAdapter.test.ts
@@ -0,0 +1,82 @@
+import type { Server } from 'node:http';
+
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+const websocketMocks = vi.hoisted(() => {
+  let connectionHandler: ((socket: FakeWebSocket, request: unknown) => void) | undefined;
+
+  class FakeWebSocket {
+    static readonly OPEN = 1;
+
+    readyState = FakeWebSocket.OPEN;
+    close = vi.fn();
+    handlers = new Map<string, Array<(...args: unknown[]) => void>>();
+
+    on(event: string, handler: (...args: unknown[]) => void) {
+      this.handlers.set(event, [...(this.handlers.get(event) ?? []), handler]);
+      return this;
+    }
+
+    emit(event: string, ...args: unknown[]) {
+      const handlers = this.handlers.get(event) ?? [];
+      if (event === 'error' && handlers.length === 0) {
+        throw args[0];
+      }
+      for (const handler of handlers) {
+        handler(...args);
+      }
+    }
+  }
+
+  class FakeWebSocketServer {
+    clients = new Set<FakeWebSocket>();
+
+    on(event: string, handler: (socket: FakeWebSocket, request: unknown) => void) {
+      if (event === 'connection') {
+        connectionHandler = handler;
+      }
+      return this;
+    }
+
+    close(callback: () => void) {
+      callback();
+    }
+  }
+
+  return {
+    FakeWebSocket,
+    FakeWebSocketServer,
+    getConnectionHandler: () => connectionHandler,
+  };
+});
+
+vi.mock('ws', () => ({
+  WebSocket: websocketMocks.FakeWebSocket,
+  WebSocketServer: websocketMocks.FakeWebSocketServer,
+}));
+
+vi.mock('../../middleware/authenticate.js', () => ({
+  authenticateSocket: (_socket: unknown, _request: unknown, next: (error?: Error) => void) => {
+    next(new Error('Unauthorized'));
+  },
+}));
+
+import { socket } from '../WebsocketAdapter.js';
+
+describe('WebsocketAdapter authentication', () => {
+  afterEach(async () => {
+    await socket.shutdown();
+  });
+
+  it('handles an error emitted while rejecting an unauthenticated socket', () => {
+    socket.init({} as Server, false);
+    const rejectedSocket = new websocketMocks.FakeWebSocket();
+    const connectionHandler = websocketMocks.getConnectionHandler();
+
+    expect(connectionHandler).toBeDefined();
+    connectionHandler?.(rejectedSocket, {});
+
+    expect(rejectedSocket.close).toHaveBeenCalledWith(1008, 'Unauthorized');
+    expect(() => rejectedSocket.emit('error', new Error('socket closed'))).not.toThrow();
+  });
+});