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.
Published: 2026-09-09
Score: 7.5 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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History

Wed, 09 Sep 2026 21:00:00 +0000

Type Values Removed Values Added
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.
Title Open WebUI: Unauthenticated requests can stall the server via uncached OIDC fetches in back-channel logout
Weaknesses CWE-405
CWE-770
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-09T20:54:26.207Z

Reserved: 2026-09-08T16:44:23.783Z

Link: CVE-2026-87011

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-09T21:17:05.847

Modified: 2026-09-09T21:17:05.847

Link: CVE-2026-87011

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-405

    Asymmetric Resource Consumption (Amplification)

  • CWE-770

    Allocation of Resources Without Limits or Throttling