CVE-2026-59216

Open WebUI: Cross-user code-interpreter and tool execution via unvalidated Socket.IO event-caller session_id

# 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', {...}, to=session_id, ...)   # delivered to that sid

# backend/open_webui/main.py
metadata = {
    'user_id': user.id,                               # server-derived (trustworthy)
    'session_id': form_data.pop('session_id', None),  # client-controlled
    ...
}

• Any victim: arbitrary code-interpreter Python and tool execution in the victim's authenticated session, the attacker acts with the victim's identity and origin (full session/account compromise).
• Admin victim: the hijacked admin context reaches POST /api/v1/functions/create, whose source is exec()'d server-side → remote code execution as the server process (root in the default container).

The Functions API is intended administrator code-execution; the vulnerability here is the cross-user delivery that lets an attacker drive another user's session, including an admin's, into it. The primitive is a full session compromise even against non-admin victims.

Untrusted input is evaluated as executable code within the application's runtime environment. Typical impact: arbitrary code execution within the application's privilege context.

CVE-2026-59216 has a CVSS score of 7.7 (High). The vector is network-reachable, low privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.10.0); upgrading removes the vulnerable code path.

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get_event_call must verify the target session belongs to the requesting user before delivering, not merely that it is connected:

session = SESSION_POOL.get(session_id)
if session is None or session.get('id') != request_info.get('user_id'):
    return {'error': 'Client session disconnected.'}

user_id in the request metadata is server-derived from the authenticated user, so it is trustworthy. Restricting ydoc:document:join so it does not disclose other participants' socket ids is recommended as defence-in-depth.

1. What is CVE-2026-59216? CVE-2026-59216 is a high-severity code injection vulnerability in open-webui (pip), affecting versions < 0.10.0. It is fixed in 0.10.0. Untrusted input is evaluated as executable code within the application's runtime environment.
2. How severe is CVE-2026-59216? CVE-2026-59216 has a CVSS score of 7.7 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of open-webui are affected by CVE-2026-59216? open-webui (pip) versions < 0.10.0 is affected.
4. Is there a fix for CVE-2026-59216? Yes. CVE-2026-59216 is fixed in 0.10.0. Upgrade to this version or later.
5. Is CVE-2026-59216 exploitable, and should I be worried? Whether CVE-2026-59216 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-59216 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-59216? Upgrade open-webui to 0.10.0 or later.

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