Authorization bypass through user-controlled key in Open WebUI - CVE-2026-45349
Published: May 11, 2026
Vulnerability identifier: #VU130945
CSH Severity: Low
CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-45349
CWE-ID: CWE-639
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to disclose sensitive information and modify another user's conversation.
The vulnerability exists due to authorization bypass through a user-controlled key in the /api/chat/completions endpoint when handling requests that reference an existing chat by chat_id. A remote user can send a request with their own API key and another user's chat ID to disclose sensitive information and modify another user's conversation.
Exploitation requires knowledge of another user's chat ID, and both users must have access to the same model.
Affected software
Open WebUI
How to mitigate CVE-2026-45349
Install security update from vendor's website.
Open WebUI - update to 0.9.0