What’s Vulnerable › Vulnerabilities

CVE-2026-87011: Open WebUI: Unauthenticated requests can stall the server via uncached OIDC fetches in back-channel logout

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-09-09 · updated 2026-09-15
• Weakness: CWE-405

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.

Affected products

• open-webui: from 0.9.0 before 0.11.1 — fixed in 0.11.1

How to fix

Upgrade to a fixed version: open-webui 0.11.1. Check the vendor advisory for mitigations.

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

Get alerted when CVE-2026-87011 or the next vulnerability affects your stack