CVE-2026-87994

Low

No strong exploitation signal.

CVSS base

4.3 MEDIUM

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

EPSS — probability of exploitation (30 days)

0.2%

12.4th percentile

CISA KEV

Not listed

Weakness / dates

CWE-639

Published 2026-09-09 · modified 2026-09-16

CVSS breakdown

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

Attack Vector	N	Network
Attack Complexity	L	Low
Privileges Required	L	Low
User Interaction	N	None
Scope	U	Unchanged
Confidentiality	N	None
Integrity	L	Low
Availability	N	None

Timeline

2026-09-09 — Published (NVD)
2026-09-16 — Last modified (NVD)

Description

Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.5 until 0.11.1, the channel branch of chat_completion in backend/open_webui/main.py checked channel write access and channel membership for a supplied message_id but did not verify that the calling user authored the targeted message. A channel member could use the chat completions endpoint to replace another member's message while preserving the victim as the stored author, altering the conversation record without gaining access to other channels. This issue is fixed in version 0.11.1.

Affected

openwebui

References

Official: NVD · CVE.org