Global Knowledge Base Enumeration via knowledge-bases Meta-Collection

{
  "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-2026-44557"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-200",
      "CWE-862"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-08T19:51:33Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "# Global Knowledge Base Enumeration via knowledge-bases Meta-Collection\n\n## Affected Component\n\nRetrieval collection access validation:\n- `backend/open_webui/routers/retrieval.py` (lines 2330-2355, `_validate_collection_access`)\n- `backend/open_webui/routers/retrieval.py` (query endpoints, e.g. `POST /query/doc`)\n\n## Affected Versions\n\nCurrent main branch (commit `6fdd19bf1`) and likely all versions with the knowledge base subsystem.\n\n## Description\n\nThe `_validate_collection_access` function uses an incomplete allowlist that only enforces ownership checks for collections matching `user-memory-*` and `file-*` patterns. All other collection names pass through unchecked \u2014 including the system-level `knowledge-bases` meta-collection, which stores the IDs, names, and descriptions of every knowledge base on the instance.\n\nAny authenticated user can query this meta-collection directly via the retrieval query endpoints to obtain a global index of all knowledge bases across all users.\n\n```python\n# retrieval.py:2330-2355 \u2014 incomplete collection allowlist\ndef _validate_collection_access(user, collection_name, ...):\n    if collection_name.startswith(\u0027user-memory-\u0027):\n        # Check user-memory ownership\n        ...\n    elif collection_name.startswith(\u0027file-\u0027):\n        # Check file access\n        ...\n    # Everything else (including \"knowledge-bases\") passes through unchecked\n```\n\nThis finding is the enabler for the KB destruction (`process/web`), KB content injection (`process/file`), and RAG vector search access bypass findings \u2014 all of which require knowing a target KB\u0027s UUID. Without this enumeration, UUIDs are random and practically unguessable; with it, UUIDs across the entire instance are trivially obtained.\n\n## CVSS 3.1 Breakdown\n\n| Metric | Value | Rationale |\n|--------|-------|-----------|\n| Attack Vector | Network (N) | Exploited remotely via API call |\n| Attack Complexity | Low (L) | Single API call |\n| Privileges Required | Low (L) | Requires any authenticated user account |\n| User Interaction | None (N) | No victim interaction required |\n| Scope | Unchanged (U) | Impact within the knowledge base boundary |\n| Confidentiality | Low (L) | Discloses KB metadata (IDs, names, descriptions) across all users |\n| Integrity | None (N) | No direct data modification |\n| Availability | None (N) | No denial of service |\n\n## Attack Scenario\n\n1. Attacker (any authenticated user) sends:\n   ```\n   POST /api/v1/retrieval/query/doc\n   {\n     \"collection_name\": \"knowledge-bases\",\n     \"query\": \"confidential\"\n   }\n   ```\n2. `_validate_collection_access` does not recognize the `knowledge-bases` prefix and lets the request pass.\n3. The vector search returns the most relevant documents from the meta-collection \u2014 knowledge base records including their UUIDs, names, and descriptions \u2014 across all users on the instance.\n4. Attacker varies the query to enumerate more KBs: `\"project\"`, `\"internal\"`, `\"private\"`, etc.\n5. Attacker now has a full target list for subsequent attacks (destruction, poisoning, content extraction).\n\n## Impact\n\n- **Information disclosure:** KB names and descriptions may reveal sensitive project names, internal initiatives, or user activities\n- **Enabler for other attacks:** Unlocks the following findings by supplying the required target UUIDs:\n  - KB destruction/poisoning via `process/web`\n  - Cross-user content injection via `process/file`\n  - RAG vector search access bypass in `retrieval/utils.py`\n- Transforms these from theoretical (requires UUID guessing) to trivially exploitable (UUIDs enumerable)\n\n## Preconditions\n\n- Attacker must have a valid user account",
  "id": "GHSA-6c2x-gcp3-gp73",
  "modified": "2026-05-08T19:51:33Z",
  "published": "2026-05-08T19:51:33Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-6c2x-gcp3-gp73"
    },
    {
      "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:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Open WebUI vulnerable to Global Knowledge Base Enumeration via knowledge-bases Meta-Collection"
}