Improper Authorization in Open WebUI - #VU130947
Published: May 11, 2026
Vulnerability identifier: #VU130947
CSH Severity: Low
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: N/A
CWE-ID: CWE-285
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
Open WebUI
Open WebUI
Software vendor:
Open WebUI
Open WebUI
Description
The vulnerability allows a remote user to bypass model access control and invoke restricted models.
The vulnerability exists due to improper authorization in the /openai/chat/completions and /ollama/api/chat HTTP endpoints when handling requests with the exposed bypass_filter query parameter. A remote user can append ?bypass_filter=true to a request URL to bypass model access control and invoke restricted models.
The issue affects the FastAPI route handlers generate_chat_completion in routers/openai.py and routers/ollama.py, where an internal-only parameter is bound from the query string.
Remediation
Install security update from vendor's website.