CVE-2026-87011
HIGHDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Exploit Intelligence
Low risk: more likely to be exploited than 29% of all known CVEs.
References
Related Vulnerabilities
Other CWE-405 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2019-11479 | High | 7.5 | 92% | - | Fix |
| CVE-2024-11187 | High | 7.5 | 17% | - | Fix |
| CVE-2025-8677 | High | 7.5 | 11% | - | Fix |
| CVE-2021-38447 | High | 8.6 | 2.1% | - | Fix |
| CVE-2021-21359 | Medium | 5.9 | 1.7% | - | Fix |
| CVE-2018-15492 | High | 7.5 | 1.2% | - | - |
Common questions
How do I fix CVE-2026-87011?
Upgrade open-webui to 0.11.1 or later.
Is CVE-2026-87011 being actively exploited?
Not that we know of. CVE-2026-87011 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.36% is the estimated probability that it will be exploited in the next 30 days. That is higher than 29% of all scored CVEs.
How severe is CVE-2026-87011?
CVE-2026-87011 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-87011 affect?
Published advisories record a fix for open-webui (PyPI (Python)). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-15.