Описание
Open WebUI Missing Access Check on Channel Members Endpoint for Standard Channels
Missing Access Check on Channel Members Endpoint for Standard Channels
Affected Component
Channel members listing endpoint:
backend/open_webui/routers/channels.py(lines 445-507,get_channel_members_by_id)
Affected Versions
Current main branch and likely all versions with the channels feature.
Description
The GET /api/v1/channels/{id}/members endpoint only checks membership for group and dm channel types (lines 467-469). For standard channels — including private ones — there is no channel_has_access check before returning the member list. Any authenticated user who knows a private channel's UUID can enumerate all users with access to that channel.
Compare with other channel endpoints (e.g., get_channel_messages at line 688) which correctly call channel_has_access(user.id, channel, permission='read') for standard channels.
CVSS 3.1 Breakdown
| Metric | Value | Rationale |
|---|---|---|
| Attack Vector | Network (N) | Exploited remotely via API call |
| Attack Complexity | Low (L) | Single API call, no special conditions |
| Privileges Required | Low (L) | Requires a valid user account |
| User Interaction | None (N) | No victim interaction required |
| Scope | Unchanged (U) | Impact is within the channel authorization boundary |
| Confidentiality | Low (L) | Leaks user identities and details for a private channel |
| Integrity | None (N) | No data modification |
| Availability | None (N) | No denial of service |
Attack Scenario
- Attacker obtains a private standard channel's UUID (via logs, browser history, URL observation, or other API responses).
- Attacker calls
GET /api/v1/channels/{id}/members. - The server returns the full list of permitted users including their IDs, names, emails, roles, and profile images.
- The attacker has no access to the channel's messages (those endpoints check access correctly), but now knows exactly who does.
Impact
- Leaks the identity and personal details of every user with access to a private channel
- Reveals organizational structure and project assignments
- Enables targeted social engineering against channel members
Preconditions
- Channels feature must be enabled (disabled by default)
- Attacker must know the channel UUID (not guessable, but obtainable through indirect means)
Пакеты
open-webui
<= 0.8.12
0.9.0
Связанные уязвимости
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the GET /api/v1/channels/{id}/members endpoint only checks membership for group and dm channel types (lines 467-469). For standard channels — including private ones — there is no channel_has_access check before returning the member list. Any authenticated user who knows a private channel's UUID can enumerate all users with access to that channel. This vulnerability is fixed in 0.9.0.
Уязвимость веб-интерфейса на базе искусственного интеллекта Open WebUI, связанная с отсутствием авторизации, позволяющая нарушителю получить несанкционированный доступ к защищаемой информации