CVE-2026-45339 — Open WebUI: API key endpoint restrictions bypassed via `x-api-key` header — full message processing on restricted endpoints
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, Open WebUI allows admins to restrict which API endpoints an AP…
Published: 2026-05-15 · CVSS: 6.5 · CVSS 3.1
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, Open WebUI allows admins to restrict which API endpoints an API key can access. When an API key is restricted from /api/v1/messages, requests using the Authorization: Bearer sk-... header are correctly blocked with 403. However, the same key sent via the x-api-key header bypasses the restriction entirely — the request is authenticated, the model is invoked, and a full response is returned. This vulnerability is fixed in 0.9.0.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7