| Package | Affected versions | Patched versions |
|---|---|---|
| open-webui | < 0.9.0 | 0.9.0 |
| open webui | < 0.9.0 | 0.9.0 |
Channel members listing endpoint:
backend/open_webui/routers/channels.py (lines 445-507, get_channel_members_by_id)Current main branch and likely all versions with the channels feature.
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.
# Line 467-469: only group/dm channels are checked
if channel.type in ['group', 'dm']:
if not Channels.is_user_channel_member(channel.id, user.id, db=db):
raise HTTPException(...)
# Standard channels fall through with NO access check
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.
| 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 |
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