Authorization bypass through user-controlled key in Open WebUI - CVE-2026-87994
Published: September 28, 2026
Vulnerability identifier: #VU152696
CSH Severity: Low
CVSS v4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-87994
CWE-ID: CWE-639
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to modify another channel member's message while preserving the original author's identity.
The vulnerability exists due to missing authorization in the channel branch of the chat completions handler when processing a client-supplied message identifier for a channel. A remote user can submit a chat completion request targeting another member's message to modify another channel member's message while preserving the original author's identity.
Channels must be enabled, and exploitation requires write access to the target channel and knowledge of the target message identifier.
Affected software
Open WebUI
How to mitigate CVE-2026-87994
Install security update from vendor's website.
Open WebUI - update to 0.11.1