{"cve":"CVE-2026-87011","nvd":{"published":"2026-09-09T21:17:05.847","modified":"2026-09-15T16:26:18.880","status":"Analyzed","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-405","CWE-770"],"references":["https://github.com/open-webui/open-webui/commit/aeda6ff13a25d3b3ba1b303609f35382db22142c","https://github.com/open-webui/open-webui/releases/tag/v0.11.1","https://github.com/open-webui/open-webui/security/advisories/GHSA-3g9q-v48f-hh9w","https://github.com/open-webui/open-webui/security/advisories/GHSA-3g9q-v48f-hh9w"],"products":["openwebui:open_webui"],"source":"nvd","synced_at":"2026-10-19T22:52:53.108888569+00:00"},"epss":{"cve":"CVE-2026-87011","score":0.00644,"percentile":0.50872,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-3g9q-v48f-hh9w","url":"https://osv.dev/vulnerability/GHSA-3g9q-v48f-hh9w","summary":"Open WebUI: Unauthenticated requests can stall the server via uncached OIDC fetches in back-channel logout","modified":"2026-10-01T17:55:42.896046627Z","packages":[{"ecosystem":"PyPI","name":"open-webui","purl":"pkg:pypi/open-webui","ranges":[">=0.9.0 <0.11.1"],"fixed":["0.11.1"]}]},{"id":"PYSEC-2026-4117","url":"https://osv.dev/vulnerability/PYSEC-2026-4117","summary":"Open WebUI: Unauthenticated requests can stall the server via uncached OIDC fetches in back-channel logout","modified":"2026-10-01T17:45:06.262359472Z","packages":[{"ecosystem":"PyPI","name":"open-webui","purl":"pkg:pypi/open-webui","ranges":[">=0.9.0 <0.11.1"],"fixed":["0.11.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}