Missing Authorization in Open WebUI - #VU152706
Published: September 28, 2026
Vulnerability identifier: #VU152706
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-862
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to add chats to a shared folder after their write access has been revoked.
The vulnerability exists due to missing authorization in the chat fork handler in `backend/open_webui/routers/chats.py` when forking a previously created chat through `POST /api/v1/chats/{id}/fork`. A remote user can fork a chat created while they had write access to add chats to a shared folder after their write access has been revoked.
Exploitation requires that the user was previously granted write access to the shared folder, created a chat there, and was later downgraded to read-only access.
Affected software
Open WebUI
Remediation
Install security update from vendor's website.
Open WebUI - update to 0.11.4