CVE-2026-87015

Low

No strong exploitation signal.

CVSS base

6.8 MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

EPSS — probability of exploitation (30 days)

0.3%

21.5th percentile

CISA KEV

Not listed

Weakness / dates

CWE-201

Published 2026-09-09 · modified 2026-09-15

CVSS breakdown

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

Attack Vector	N	Network
Attack Complexity	H	High
Privileges Required	N	None
User Interaction	R	Required
Scope	U	Unchanged
Confidentiality	H	High
Integrity	H	High
Availability	N	None

Timeline

2026-09-09 — Published (NVD)
2026-09-15 — Last modified (NVD)

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

openwebui

References

Official: NVD · CVE.org