Stale Admin Role in Socket.IO Session Pool Enables Post-Demotion Cross-User Note Access

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.8.12"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "open-webui"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.9.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-44553"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-384",
      "CWE-863"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-08T19:43:49Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "# Stale Admin Role in Socket.IO Session Pool Enables Post-Demotion Cross-User Note Access\n\n## Affected Component\n\nSocket.IO session state and role-check callsites:\n- `backend/open_webui/socket/main.py` (lines 330-351, `connect` handler \u2014 role snapshotted into SESSION_POOL)\n- `backend/open_webui/socket/main.py` (lines 393-398, `heartbeat` handler \u2014 does not refresh role)\n- `backend/open_webui/socket/main.py` (line 538, `ydoc:document:join` \u2014 uses cached role for admin check)\n- `backend/open_webui/socket/main.py` (line 611, `document_save_handler` \u2014 uses cached role for admin check)\n- `backend/open_webui/routers/users.py` (lines 557-633, role update \u2014 does not invalidate SESSION_POOL)\n- `backend/open_webui/routers/users.py` (line 641, user delete \u2014 does not invalidate SESSION_POOL)\n\n## Affected Versions\n\nCurrent main branch (commit `6fdd19bf1`) and likely all versions with the collaborative document (Yjs) Socket.IO handlers.\n\n## Description\n\nWhen a user connects via Socket.IO, the `connect` handler authenticates them via JWT and stores their user record (including `role`) in the in-memory `SESSION_POOL` dictionary keyed by session ID. The `heartbeat` handler keeps the session alive indefinitely but only refreshes the `last_seen_at` timestamp \u2014 never the role.\n\nRole checks in the Yjs collaborative document handlers (`ydoc:document:join`, `document_save_handler`) consult the cached `SESSION_POOL` role rather than the database. Meanwhile, administrative role changes and user deletions do not iterate `SESSION_POOL` to disconnect affected sessions. As a result, a user whose admin role has been revoked retains admin privileges within their existing Socket.IO session for as long as they keep the connection alive (via automatic heartbeats).\n\nHTTP endpoints are not affected \u2014 `get_current_user` at [utils/auth.py](backend/open_webui/utils/auth.py) refetches the user record from the database on every request. The gap is exclusive to the Socket.IO session cache.\n\n```python\n# socket/main.py:330-351 \u2014 role snapshotted at connect time\nasync def connect(sid, environ, auth):\n    user = None\n    if auth and \u0027token\u0027 in auth:\n        data = decode_token(auth[\u0027token\u0027])\n        if data is not None and \u0027id\u0027 in data:\n            user = Users.get_user_by_id(data[\u0027id\u0027])\n        if user:\n            SESSION_POOL[sid] = {\n                \u0027id\u0027: user.id,\n                \u0027role\u0027: user.role,   # \u2190 snapshotted, never refreshed\n                ...\n            }\n\n# socket/main.py:393-398 \u2014 heartbeat refreshes last_seen_at only\nasync def heartbeat(sid, data):\n    user = SESSION_POOL.get(sid)\n    if user:\n        SESSION_POOL[sid] = {**user, \u0027last_seen_at\u0027: int(time.time())}\n        # role is carried forward unchanged\n\n# socket/main.py:538 \u2014 admin check against cached role\nif user.get(\u0027role\u0027) != \u0027admin\u0027 and not has_access(user_id, \u0027note\u0027, note_id, \u0027read\u0027, db=db):\n    return\n```\n\n## Attack Scenario\n\n1. User B is an admin and has an active browser session with a live Socket.IO connection. `SESSION_POOL[sid]` records `role=\u0027admin\u0027`.\n2. Admin A demotes User B to a regular user via `POST /api/v1/users/{B_id}/update`. The DB `user.role` becomes `\u0027user\u0027`.\n3. No Socket.IO disconnect, no SESSION_POOL update, no token revocation event is triggered by the role change.\n4. User B\u0027s client continues sending `heartbeat` events every few seconds; these are accepted and only refresh `last_seen_at`.\n5. User B emits `ydoc:document:join` with `document_id = \u0027note:\u003cvictim_note_id\u003e\u0027` for any note they do not own.\n6. The handler at line 538 evaluates `user.get(\u0027role\u0027) != \u0027admin\u0027` \u2014 returns `False` because `SESSION_POOL` still holds the stale `admin` role. Access check is bypassed, User B joins the document room, receives full document state and live updates.\n7. User B emits `ydoc:document:update` for the same note. The handler at line 611 performs the same cached-admin check, bypasses authorization, and persists attacker-controlled content to the victim\u0027s note via `Notes.update_note_by_id`.\n\nThe same bypass occurs if the user is deleted entirely (`delete_user_by_id`) \u2014 the deleted user retains admin privileges on their live socket until disconnection.\n\n## Impact\n\n- Read access to any user\u0027s notes after admin privileges have been revoked\n- Write access (content injection, overwrite) to any user\u0027s notes under the same conditions\n- The stale privilege is bounded only by the attacker\u0027s willingness to keep the Socket.IO connection alive; heartbeats extend the session indefinitely\n- Official admin demotion or user deletion gives a false sense of security \u2014 HTTP access is correctly revoked, but real-time collaborative access silently continues\n\n## Preconditions\n\n- Attacker must have an active Socket.IO connection established while they held admin role\n- Attacker must retain the Socket.IO session after demotion/deletion (trivial \u2014 just don\u0027t close the browser)",
  "id": "GHSA-45m8-cpm2-3v65",
  "modified": "2026-05-08T19:43:49Z",
  "published": "2026-05-08T19:43:49Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-45m8-cpm2-3v65"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/open-webui/open-webui"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Open WebUI: Stale Admin Role in Socket.IO Session Pool Enables Post-Demotion Cross-User Note Access"
}