CVE-2026-87015

Analyzed Analyzed - Analysis Complete

Session Cookie Exposure in Open WebUI

Publication date: 2026-09-09

Last updated on: 2026-09-15

Assigner: GitHub, Inc.

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.

CVSS Scores

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Meta Information

Published

2026-09-09

Last Modified

2026-09-15

Generated

2026-09-30

AI Q&A

2026-09-10

EPSS Evaluated

2026-09-29

NVD

CVE-2026-87015

Affected Vendors & Products

Vendor	Product	Version / Range
openwebui	open_webui	From 0.6.27 (inc) to 0.11.1 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-201	The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor.

Attack-Flow Graph

Executive Summary

Open WebUI versions 0.6.27 to 0.11.0 had a flaw where session cookies were captured in a shared jar instead of being bound to specific tool calls. If OAuth connections were processed last, requests to other servers using bearer authentication could include the user's Open WebUI session cookies. This allowed those servers' operators to reuse the session and take over the user's account.

Detection Guidance

This vulnerability involves improper cookie handling in Open WebUI versions 0.6.27 to 0.11.0. To detect it, check your Open WebUI version with: docker inspect open-webui | grep -i version or cat /app/open-webui/version.txt. If the version is between 0.6.27 and 0.11.0, the system is vulnerable.

Impact Analysis

If you used Open WebUI versions between 0.6.27 and 0.11.0 with multiple tool servers and OAuth connections, an attacker controlling a different server could hijack your Open WebUI session. This could lead to unauthorized access to your account, data exposure, or further attacks using your identity.

Compliance Impact

This vulnerability could lead to unauthorized access to user data, violating confidentiality requirements under GDPR and HIPAA. It may result in data breaches, requiring breach notifications and potential fines for non-compliance with security and privacy controls.

Mitigation Strategies

Upgrade Open WebUI to version 0.11.1 or later to address the session cookie leakage issue in tool server authentication.

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