Authorization bypass through user-controlled key in Open WebUI - #VU146343
Published: August 31, 2026
Vulnerability identifier: #VU146343
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: N/A
CWE-ID: CWE-639
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to inject chats into another user\'s folder.
The vulnerability exists due to missing authorization in the chat-completions handler in backend/open_webui/main.py when handling POST requests to /api/chat/completions and /api/v1/chat/completions with a user-supplied folder id. A remote user can send a crafted request with a target folder id to inject chats into another user\'s folder.
Folders must be enabled, and exploitation requires knowledge of the target folder id. Shared folders with read-only access are reachable, while unshared folders are not practically reachable through available endpoints.
Affected software
Open WebUI
Remediation
Install security update from vendor's website.
Open WebUI - update to 0.11.1