What’s Vulnerable › Vulnerabilities

CVE-2026-87015: Open WebUI: A user's session cookies are sent to tool servers configured for bearer authentication

• Severity: medium (CVSS 6.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-09-09 · updated 2026-09-15
• Weakness: CWE-201

Description

Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.6.27 until 0.11.1, backend/open_webui/utils/tools.py captured a cookie jar from the enclosing connection loop instead of binding it to each external tool callable. When multiple tool servers were attached and a session or system OAuth connection was processed last, a request to a different server configured for bearer authentication could include the calling user's Open WebUI session cookies, allowing that server's operator to reuse the session and take over the account. This issue is fixed in version 0.11.1.

Affected products

• open-webui: from 0.6.27 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/cd9db21c5276807a2975ddba17cef369ad1114b7
• https://github.com/open-webui/open-webui/pull/28630
• https://github.com/open-webui/open-webui/releases/tag/v0.11.1
• https://github.com/open-webui/open-webui/security/advisories/GHSA-p78m-89r6-pgf7
• https://github.com/open-webui/open-webui/security/advisories/GHSA-p78m-89r6-pgf7

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