diff --git a/backend/open_webui/socket/main.py b/backend/open_webui/socket/main.py
index 72d516cf22..302e2f6f86 100644
--- a/backend/open_webui/socket/main.py
+++ b/backend/open_webui/socket/main.py
@@ -6,6 +6,7 @@ import logging
 import random
 import sys
 import time
+import weakref
 from contextlib import suppress
 from typing import Any
 
@@ -209,6 +210,7 @@ REDIS_EVENT_CHANNEL = f'{REDIS_KEY_PREFIX}:direct_completion'
 
 EVENT_QUEUES: dict[str, asyncio.Queue] = {}
 EVENT_PUBLISH_LOCK = asyncio.Lock()
+SESSION_EVENT_LOCKS: weakref.WeakValueDictionary[str, asyncio.Lock] = weakref.WeakValueDictionary()
 
 
 def get_session_pool_batches():
@@ -1068,19 +1070,22 @@ async def socket_event_handler(event: Any, sid: str, *args: Any) -> None:
     if not isinstance(event, str) or event.count(':') != 2 or not args:
         return
 
-    user = await get_socket_session_user(sid)
-    if not user or user.get('id') != event.split(':', 1)[0]:
-        return
+    # The lock keeps arrival order; the sid re-check drops every event after a failed check
+    session_check = asyncio.create_task(get_socket_session_user(sid))
+    async with SESSION_EVENT_LOCKS.setdefault(sid, asyncio.Lock()):
+        user = await session_check
+        if not user or sid not in LOCAL_AUTHENTICATED_SIDS or user.get('id') != event.split(':', 1)[0]:
+            return
 
-    queue = EVENT_QUEUES.get(event)
-    if queue is not None:
-        await queue.put(args[0])
-    elif WEBSOCKET_MANAGER == 'redis':
-        try:
-            async with EVENT_PUBLISH_LOCK:
-                await REDIS.publish(REDIS_EVENT_CHANNEL, dumps_bytes({'channel': event, 'data': args[0]}))
-        except RedisError as e:
-            log.debug('Failed to relay socket event %s: %s', event, e)
+        queue = EVENT_QUEUES.get(event)
+        if queue is not None:
+            await queue.put(args[0])
+        elif WEBSOCKET_MANAGER == 'redis':
+            try:
+                async with EVENT_PUBLISH_LOCK:
+                    await REDIS.publish(REDIS_EVENT_CHANNEL, dumps_bytes({'channel': event, 'data': args[0]}))
+            except RedisError as e:
+                log.debug('Failed to relay socket event %s: %s', event, e)
 
 
 async def _make_channel_emitter(request_info):