Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.5 until 0.11.1, the channel branch of chat_completion in backend/open_webui/main.py checked channel write access and channel membership for a supplied message_id but did not verify that the calling user authored the targeted message. A channel member could use the chat completions endpoint to replace another member's message while preserving the victim as the stored author, altering the conversation record without gaining access to other channels.
This issue is fixed in version 0.11.1.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
Low
Partial data modification
Availability
None
No disruption
CVSS Vector v3.1
Weakness Type (CWE)
References 4
https://github.com/open-webui/open-webui/commit/7d392bedc9c1aaecc94509a58e59186…
security-advisories@github.com
https://github.com/open-webui/open-webui/pull/28631
security-advisories@github.com
https://github.com/open-webui/open-webui/releases/tag/v0.11.1
security-advisories@github.com
https://github.com/open-webui/open-webui/security/advisories/GHSA-fmqh-xp37-5hr8
security-advisories@github.com