GHSA-74H3-CXQ7-VC5Q

Vulnerability from github – Published: 2026-07-24 17:01 – Updated: 2026-07-24 17:01
VLAI
Summary
Open WebUI: Cross-user code-interpreter and tool execution via unvalidated Socket.IO event-caller session_id
Details

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:

# 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

session_id originates from the request body and is never validated against the authenticated user:

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

SESSION_POOL[session_id] is the user record of whoever owns that socket. Because the caller checks only membership (in SESSION_POOL), a request carrying another user's session_id causes execute:python / execute:tool to be delivered to that other user's browser.

Reachability

  • execute:python / execute:tool are emitted from the code-interpreter and tool-call paths (utils/middleware.py, tools/builtin.py), all routed through get_event_call.
  • The victim's live session_id is disclosed to any read-access participant of a shared note via ydoc:document:join.
  • POST /api/v1/chat/completions requires only get_verified_user (the default user role). The attacker uses their own account and a model / Direct Connection they control to choose the payload.

Impact

  • 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.

Proof of Concept

The reporter's exploit.py reproduced on ghcr.io/open-webui/open-webui:0.9.6 and a build of the v0.9.6 tag, confirming blind server-side RCE out-of-band (callback returns uid=0(root)), using only a low-privilege user account that shared a note with an admin victim. Preconditions: code interpreter enabled; attacker shares a note with the victim; victim opens it while online; admin victim required for server RCE.

Fix

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.

Affected / Patched

  • Affected: < 0.10.0 (last affected release 0.9.6)
  • Patched: v0.10.0. get_event_call now verifies the target session belongs to the requesting user before delivering (session is None or session.get('id') != request_info.get('user_id')), using the server-derived user_id from the request metadata. The recommended ydoc:document:join sid-disclosure restriction is defence-in-depth and independent of this fix; the ownership check closes the cross-user delivery regardless of whether the victim's sid is known.
Severity
7.7 (High)
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "open-webui"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.10.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-59216"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-200",
      "CWE-639",
      "CWE-862",
      "CWE-94"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-24T17:01:53Z",
    "nvd_published_at": "2026-07-09T17:17:02Z",
    "severity": "HIGH"
  },
  "details": "## Summary\n\nAn authenticated low-privilege user can execute arbitrary code-interpreter Python and tools inside **another** user\u0027s 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\u0027s collaboration room to any read-access participant, an attacker can target a victim\u0027s session and run attacker-chosen code/tools in the victim\u0027s 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).\n\n## Affected component\n\n- `backend/open_webui/socket/main.py` \u2014 `get_event_call()` / `__event_caller__`\n- `backend/open_webui/main.py` \u2014 chat-completion metadata (`session_id` taken from the request body)\n\n## Root cause\n\nThe event-caller routes to a caller-controlled session id with no ownership check:\n\n```python\n# backend/open_webui/socket/main.py \u2014 get_event_call()\nasync def __event_caller__(event_data):\n    session_id = request_info[\u0027session_id\u0027]\n    if session_id not in SESSION_POOL:                 # only checks the session is connected\n        return {\u0027error\u0027: \u0027Client session disconnected.\u0027}\n    return await sio.call(\u0027events\u0027, {...}, to=session_id, ...)   # delivered to that sid\n```\n\n`session_id` originates from the request body and is never validated against the authenticated user:\n\n```python\n# backend/open_webui/main.py\nmetadata = {\n    \u0027user_id\u0027: user.id,                               # server-derived (trustworthy)\n    \u0027session_id\u0027: form_data.pop(\u0027session_id\u0027, None),  # client-controlled\n    ...\n}\n```\n\n`SESSION_POOL[session_id]` is the user record of whoever owns that socket. Because the caller checks only membership (`in SESSION_POOL`), a request carrying another user\u0027s `session_id` causes `execute:python` / `execute:tool` to be delivered to that other user\u0027s browser.\n\n## Reachability\n\n- `execute:python` / `execute:tool` are emitted from the code-interpreter and tool-call paths (`utils/middleware.py`, `tools/builtin.py`), all routed through `get_event_call`.\n- The victim\u0027s live `session_id` is disclosed to any read-access participant of a shared note via `ydoc:document:join`.\n- `POST /api/v1/chat/completions` requires only `get_verified_user` (the default user role). The attacker uses their own account and a model / Direct Connection they control to choose the payload.\n\n## Impact\n\n- **Any victim:** arbitrary code-interpreter Python and tool execution in the victim\u0027s authenticated session \u2014 the attacker acts with the victim\u0027s identity and origin (full session/account compromise).\n- **Admin victim:** the hijacked admin context reaches `POST /api/v1/functions/create`, whose source is `exec()`\u0027d server-side \u2192 remote code execution as the server process (root in the default container).\n\nThe Functions API is intended administrator code-execution; the vulnerability here is the cross-user delivery that lets an attacker drive another user\u0027s session \u2014 including an admin\u0027s \u2014 into it. The primitive is a full session compromise even against non-admin victims.\n\n## Proof of Concept\n\nThe reporter\u0027s `exploit.py` reproduced on `ghcr.io/open-webui/open-webui:0.9.6` and a build of the `v0.9.6` tag, confirming blind server-side RCE out-of-band (callback returns `uid=0(root)`), using only a low-privilege `user` account that shared a note with an admin victim. Preconditions: code interpreter enabled; attacker shares a note with the victim; victim opens it while online; admin victim required for server RCE.\n\n## Fix\n\n`get_event_call` must verify the target session belongs to the requesting user before delivering, not merely that it is connected:\n\n```python\nsession = SESSION_POOL.get(session_id)\nif session is None or session.get(\u0027id\u0027) != request_info.get(\u0027user_id\u0027):\n    return {\u0027error\u0027: \u0027Client session disconnected.\u0027}\n```\n\n`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\u0027 socket ids is recommended as defence-in-depth.\n\n## Affected / Patched\n\n- Affected: `\u003c 0.10.0` (last affected release 0.9.6)\n- Patched: v0.10.0. `get_event_call` now verifies the target session belongs to the requesting user before delivering (`session is None or session.get(\u0027id\u0027) != request_info.get(\u0027user_id\u0027)`), using the server-derived `user_id` from the request metadata. The recommended `ydoc:document:join` sid-disclosure restriction is defence-in-depth and independent of this fix; the ownership check closes the cross-user delivery regardless of whether the victim\u0027s sid is known.",
  "id": "GHSA-74h3-cxq7-vc5q",
  "modified": "2026-07-24T17:01:53Z",
  "published": "2026-07-24T17:01:53Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-74h3-cxq7-vc5q"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-59216"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/pull/25763"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/commit/386ac958144dbbbf0aa6e268070d72b681a318aa"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/open-webui/open-webui"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/releases/tag/v0.10.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Open WebUI: Cross-user code-interpreter and tool execution via unvalidated Socket.IO event-caller session_id"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.