{"id":"CVE-2026-87011","summary":"Open WebUI: Unauthenticated requests can stall the server via uncached OIDC fetches in back-channel logout","details":"Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.0 until 0.11.1, the unauthenticated POST /oauth/backchannel-logout handler in backend/open_webui/utils/oauth.py fetched the OIDC discovery document and signing keys before validating a submitted logout token. Each request repeated uncached network fetches, and the signing-key lookup blocked the async event loop, so requests carrying invalid tokens could stall the single-worker instance and amplify traffic to the identity provider when ENABLE_OAUTH_BACKCHANNEL_LOGOUT was enabled. This issue is fixed in version 0.11.1.","aliases":["GHSA-3g9q-v48f-hh9w","PYSEC-2026-4117"],"modified":"2026-10-28T02:30:29.938614727Z","published":"2026-09-09T20:54:26.207Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-405","CWE-770"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/87xxx/CVE-2026-87011.json"},"references":[{"type":"WEB","url":"https://github.com/open-webui/open-webui/releases/tag/v0.11.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/87xxx/CVE-2026-87011.json"},{"type":"ADVISORY","url":"https://github.com/open-webui/open-webui/security/advisories/GHSA-3g9q-v48f-hh9w"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-87011"},{"type":"FIX","url":"https://github.com/open-webui/open-webui/commit/aeda6ff13a25d3b3ba1b303609f35382db22142c"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/open-webui/open-webui","events":[{"introduced":"f31768e20e5c6b4f6da0ef657877298b359936cf"},{"fixed":"d3e8bf3405e848cfba377814d0aa7ba7290e414d"},{"fixed":"aeda6ff13a25d3b3ba1b303609f35382db22142c"}],"database_specific":{"extracted_events":[{"cpe":"cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:*","range":[{"introduced":"0.9.0"},{"fixed":"0.11.1"}],"source":"CPE_RANGE"},{"range":[{"fixed":"aeda6ff13a25d3b3ba1b303609f35382db22142c"}],"source":"REFERENCES_COMMIT"},{"source":"REFERENCES_TAG","original_tag":"v0.11.1","range":[{"fixed":"d3e8bf3405e848cfba377814d0aa7ba7290e414d"}]}]}}],"versions":["v0.11.0","v0.10.2","v0.10.1","v0.10.0","v0.9.5","v0.9.4","v0.9.3","v0.9.2","v0.9.1","v0.9.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-87011.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}