Open WebUI — Auth Bypass (CVE-2026-45365)
Date: 2026-05
Affected: openwebui/open_webui
Attack vector: auth-bypass
Category: vulnerability-disclosure
Severity: High
CVE: CVE-2026-34222
CVE-2026-45365
CVE-2026-45666
CWE: CWE-285
CWE-639
CVSS: 5.4 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N)

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.8.11, an internal-only bypass_filter parameter is exposed on the /openai/chat/completions and /ollama/api/chat HTTP endpoints via FastAPI query string binding, allowing any authenticated user to append ?bypass_filter=true and bypass model access control checks to invoke admin-restricted models. This vulnerability is fixed in 0.8.11.


Mitigations:

Architectural layers (MAESTRO):