CVE-2026-87015

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in, but needs a user to act. High risk of data exposure, data tampering.

Exploit odds

0.5% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-09-09 21:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-09-15 15:54 UTC Last updatedMost recent change to the record

Details

Published

2026-09-09 21:17 UTC

Last modified

2026-09-15 15:54 UTC

Exploit probability

0.5% · EPSS, next 30 days

Weakness

CWE-201

Record status

Analyzed

Affected

• Openwebui Open Webui < 0.11.1

Attack profile CVSS 3.1 · 6.8

Attack vector

Network

Complexity

High

Privileges needed

None

User interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None