PYSEC-2026-3599

Vulnerability from pysec - Published: 2026-08-04 11:34 - Updated: 2026-08-04 13:36
VLAI
Details

Summary

The Socket.IO server is configured with always_connect=True (lines 78, 91 in backend/open_webui/socket/main.py) and the connect handler (line 329) never rejects unauthenticated connections. Two Ydoc event handlers have zero authentication checks, allowing unauthenticated clients to interact with collaborative document sessions.

Vulnerable Code

ydoc:awareness:update (line 741) — No auth check at all

@sio.on('ydoc:awareness:update')
async def yjs_awareness_update(sid, data):
    document_id = data['document_id']
    user_id = data.get('user_id', sid)
    update = data['update']
    # No SESSION_POOL check, no room membership check
    await sio.emit(
        'ydoc:awareness:update',
        {'document_id': document_id, 'user_id': user_id, 'update': update},
        room=f'doc_{document_id}',
        skip_sid=sid,
    )

ydoc:document:leave (line 711) — No auth check at all

@sio.on('ydoc:document:leave')
async def yjs_document_leave(sid, data):
    document_id = data['document_id']
    user_id = data.get('user_id', sid)
    # No auth check
    await YDOC_MANAGER.remove_user(document_id=document_id, user_id=sid)
    await sio.emit('ydoc:user:left',
        {'document_id': document_id, 'user_id': user_id},
        room=f'doc_{document_id}')

Root Cause: always_connect=True (line 78)

sio = socketio.AsyncServer(
    always_connect=True,   # Never rejects connections
    ...
)

The connect handler (line 329) adds authenticated users to SESSION_POOL but never returns False or raises an exception for unauthenticated connections.

Exploitation

  1. An unauthenticated attacker connects via Socket.IO (no token needed)
  2. The attacker emits ydoc:awareness:update with:
  3. document_id: a known/guessed note UUID (format: note:{uuid})
  4. user_id: spoofed to impersonate any user
  5. update: arbitrary awareness data (fake cursor positions, selections)
  6. The fake awareness data is broadcast to all legitimate users in the document room
  7. The attacker can also emit ydoc:document:leave with spoofed user_id to broadcast fake ydoc:user:left events

Impact

  • UI disruption: Fake cursor positions and user presence in collaborative editing sessions
  • User impersonation: Attacker can spoof any user_id in awareness updates
  • Resource exhaustion: Unlimited unauthenticated WebSocket connections maintained by the server

Note: Other Ydoc handlers (ydoc:document:join, ydoc:document:update, ydoc:document:state) correctly check SESSION_POOL membership.

Suggested Fix

  1. Set always_connect=False or reject unauthenticated connections in the connect handler
  2. Add SESSION_POOL checks to ydoc:awareness:update and ydoc:document:leave
  3. Add room membership verification before broadcasting to document rooms

AI Disclosure (per Rule 11): AI (Claude) was used to assist with source code review, identifying potential vulnerability patterns, and drafting this report. The researcher directed the analysis, selected focus areas, and independently verified all findings against a running v0.8.12 Docker instance using real HTTP requests with two test accounts. The PoCs included are reproducible and were confirmed live before submission.

Severity
3.1 (Low)
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
Impacted products
Name purl
open-webui pkg:pypi/open-webui
Aliases
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "open-webui",
        "purl": "pkg:pypi/open-webui"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.6.16"
            },
            {
              "fixed": "0.10.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.6.16",
        "0.6.18",
        "0.6.19",
        "0.6.20",
        "0.6.21",
        "0.6.22",
        "0.6.23",
        "0.6.24",
        "0.6.25",
        "0.6.26",
        "0.6.26.dev1",
        "0.6.27",
        "0.6.28",
        "0.6.29",
        "0.6.30",
        "0.6.31",
        "0.6.32",
        "0.6.33",
        "0.6.34",
        "0.6.35",
        "0.6.36",
        "0.6.37",
        "0.6.38",
        "0.6.39",
        "0.6.40",
        "0.6.41",
        "0.6.42",
        "0.6.43",
        "0.7.0",
        "0.7.1",
        "0.7.2",
        "0.8.0",
        "0.8.1",
        "0.8.10",
        "0.8.11",
        "0.8.12",
        "0.8.2",
        "0.8.3",
        "0.8.4",
        "0.8.5",
        "0.8.6",
        "0.8.7",
        "0.8.8",
        "0.8.9",
        "0.9.0",
        "0.9.1",
        "0.9.2",
        "0.9.3",
        "0.9.4",
        "0.9.5",
        "0.9.6"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-59715",
    "GHSA-gmfw-g93r-vg53"
  ],
  "details": "## Summary\n\nThe Socket.IO server is configured with `always_connect=True` (lines 78, 91 in `backend/open_webui/socket/main.py`) and the `connect` handler (line 329) never rejects unauthenticated connections. Two Ydoc event handlers have zero authentication checks, allowing unauthenticated clients to interact with collaborative document sessions.\n\n## Vulnerable Code\n\n### `ydoc:awareness:update` (line 741) \u2014 No auth check at all\n```python\n@sio.on(\u0027ydoc:awareness:update\u0027)\nasync def yjs_awareness_update(sid, data):\n    document_id = data[\u0027document_id\u0027]\n    user_id = data.get(\u0027user_id\u0027, sid)\n    update = data[\u0027update\u0027]\n    # No SESSION_POOL check, no room membership check\n    await sio.emit(\n        \u0027ydoc:awareness:update\u0027,\n        {\u0027document_id\u0027: document_id, \u0027user_id\u0027: user_id, \u0027update\u0027: update},\n        room=f\u0027doc_{document_id}\u0027,\n        skip_sid=sid,\n    )\n```\n\n### `ydoc:document:leave` (line 711) \u2014 No auth check at all\n```python\n@sio.on(\u0027ydoc:document:leave\u0027)\nasync def yjs_document_leave(sid, data):\n    document_id = data[\u0027document_id\u0027]\n    user_id = data.get(\u0027user_id\u0027, sid)\n    # No auth check\n    await YDOC_MANAGER.remove_user(document_id=document_id, user_id=sid)\n    await sio.emit(\u0027ydoc:user:left\u0027,\n        {\u0027document_id\u0027: document_id, \u0027user_id\u0027: user_id},\n        room=f\u0027doc_{document_id}\u0027)\n```\n\n### Root Cause: `always_connect=True` (line 78)\n```python\nsio = socketio.AsyncServer(\n    always_connect=True,   # Never rejects connections\n    ...\n)\n```\n\nThe `connect` handler (line 329) adds authenticated users to `SESSION_POOL` but never returns `False` or raises an exception for unauthenticated connections.\n\n## Exploitation\n\n1. An unauthenticated attacker connects via Socket.IO (no token needed)\n2. The attacker emits `ydoc:awareness:update` with:\n   - `document_id`: a known/guessed note UUID (format: `note:{uuid}`)\n   - `user_id`: spoofed to impersonate any user\n   - `update`: arbitrary awareness data (fake cursor positions, selections)\n3. The fake awareness data is broadcast to all legitimate users in the document room\n4. The attacker can also emit `ydoc:document:leave` with spoofed `user_id` to broadcast fake `ydoc:user:left` events\n\n## Impact\n\n- **UI disruption**: Fake cursor positions and user presence in collaborative editing sessions\n- **User impersonation**: Attacker can spoof any `user_id` in awareness updates\n- **Resource exhaustion**: Unlimited unauthenticated WebSocket connections maintained by the server\n\nNote: Other Ydoc handlers (`ydoc:document:join`, `ydoc:document:update`, `ydoc:document:state`) correctly check `SESSION_POOL` membership.\n\n## Suggested Fix\n\n1. Set `always_connect=False` or reject unauthenticated connections in the `connect` handler\n2. Add `SESSION_POOL` checks to `ydoc:awareness:update` and `ydoc:document:leave`\n3. Add room membership verification before broadcasting to document rooms\n\n---\n\n\u003e **AI Disclosure (per Rule 11):** AI (Claude) was used to assist with source code review, identifying potential vulnerability patterns, and drafting this report. The researcher directed the analysis, selected focus areas, and independently verified all findings against a running v0.8.12 Docker instance using real HTTP requests with two test accounts. The PoCs included are reproducible and were confirmed live before submission.",
  "id": "PYSEC-2026-3599",
  "modified": "2026-08-04T13:36:26.443650Z",
  "published": "2026-08-04T11:34:42.643342Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-gmfw-g93r-vg53"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-59715"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/pull/25946"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/commit/22f2fe1ffb66c993dad1e0b2b35514acaed2370e"
    },
    {
      "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"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/open-webui"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-gmfw-g93r-vg53"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Open WebUI: Unauthenticated WebSocket Access to Collaborative Document Handlers (ydoc:awareness:update, ydoc:document:leave)"
}



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