PYSEC-2026-4117 Open WebUI: Unauthenticated requests can stall the server via uncached OIDC fetches in back-channel logout

Summary The OIDC back-channel logout endpoint is unauthenticated by design, because the identity provider calls it without a browser session. Before checking whether the submitted logout token was genuine, the handler fetched the provider's discovery document and its signing keys over the network...