Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. Prior to 0.10.0, get_event_call delivered execute:python and execute:tool Socket.IO events to a client-supplied session_id after checking only that the session was connected, allowing authenticated users who learned another socket ID through ydoc:document:join to run code interpreter Python or tools in that user session. This issue is fixed in version 0.10.0.

Affected: PyPI: open-webui

## Summary

An authenticated low-privilege user can execute arbitrary code-interpreter Python and tools inside **another** user's authenticated session. The Socket.IO event-caller (`get_event_call`) delivers `execute:python` / `execute:tool` events to a **client-supplied** `session_id` after only checking that the session is connected, never that it belongs to the requester. Combined with `ydoc:document:join`, which exposes the live socket ids of everyone in a shared note's collaboration room to any read-access participant, an attacker can target a victim's session and run attacker-chosen code/tools in the victim's browser context. When the victim is an administrator, that hijacked context reaches the admin-only Functions API, whose source is executed server-side, yielding remote code execution as the server process (root in the default container).

## Affected component

- `backend/open_webui/socket/main.py` — `get_event_call()` / `__event_caller__` - `backend/open_webui/main.py` — chat-completion metadata (`session_id` taken from the request body)

## Root cause

The event-caller routes to a caller-controlled session id with no ownership check:

```python # backend/open_webui/socket/main.py — get_event_call() async def __event_caller__(event_data): session_id = request_info['session_id'] if session_id not in SESSION_POOL: # only checks the session is connected return {'error': 'Client session disconnected.'} return await sio.call('events…

Affected: PyPI: open-webui

## Summary

An authenticated low-privilege user can execute arbitrary code-interpreter Python and tools inside **another** user's authenticated session. The Socket.IO event-caller (`get_event_call`) delivers `execute:python` / `execute:tool` events to a **client-supplied** `session_id` after only checking that the session is connected, never that it belongs to the requester. Combined with `ydoc:document:join`, which exposes the live socket ids of everyone in a shared note's collaboration room to any read-access participant, an attacker can target a victim's session and run attacker-chosen code/tools in the victim's browser context. When the victim is an administrator, that hijacked context reaches the admin-only Functions API, whose source is executed server-side, yielding remote code execution as the server process (root in the default container).

## Affected component

- `backend/open_webui/socket/main.py` — `get_event_call()` / `__event_caller__` - `backend/open_webui/main.py` — chat-completion metadata (`session_id` taken from the request body)

## Root cause

The event-caller routes to a caller-controlled session id with no ownership check:

```python # backend/open_webui/socket/main.py — get_event_call() async def __event_caller__(event_data): session_id = request_info['session_id'] if session_id not in SESSION_POOL: # only checks the session is connected return {'error': 'Client session disconnected.'} return await sio.call('events…