Vulnerability Details CVE-2026-87011
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.003
EPSS Ranking 27.1%
CVSS Severity
CVSS v3 Score 7.5
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 affected by CVE-2026-87011
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cpe:2.3:a:openwebui:open_webui:0.10.0
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cpe:2.3:a:openwebui:open_webui:0.10.1
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cpe:2.3:a:openwebui:open_webui:0.10.2
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cpe:2.3:a:openwebui:open_webui:0.11.0
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cpe:2.3:a:openwebui:open_webui:0.9.0
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cpe:2.3:a:openwebui:open_webui:0.9.1
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cpe:2.3:a:openwebui:open_webui:0.9.2
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cpe:2.3:a:openwebui:open_webui:0.9.3
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cpe:2.3:a:openwebui:open_webui:0.9.4
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cpe:2.3:a:openwebui:open_webui:0.9.5
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cpe:2.3:a:openwebui:open_webui:0.9.6