PT-2026-39278 · Unknown · Open-Webui

Published 2026-05-08 · Updated 2026-05-17 · CVE-2026-44561

Positive Technologies (AI Summary)

CVSS v3.1

5.4

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions Open WebUI versions prior to 0.9.0

Description Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. An issue exists where the is user channel member() function verifies the existence of a membership record but fails to check the is active field. Consequently, when a user is removed from a group or DM channel or leaves voluntarily, their membership record remains with is active=False and status='left', yet they retain full read and write access via direct API calls. While the channel is hidden from the user's interface, they can still interact with message-level endpoints if they possess the channel ID. Affected endpoints include:

• '/api/v1/channels/{channel id}/messages'
• '/api/v1/channels/{channel id}/messages/post'
• '/api/v1/channels/{channel id}/messages/{id}/update'
• '/api/v1/channels/{channel id}/messages/{id}/delete'

Recommendations Update to version 0.9.0.

Exploit

Fix

Incorrect Authorization

Improper Access Control

Weakness Enumeration

CWE-863

CWE-284

Related Identifiers

CVE-2026-44561

GHSA-HMGR-67HW-J2CQ

Affected Products

Open-Webui

References · 8

• 🔥 https://github.com/open-webui/open-webui/security/advisories/GHSA-hmgr-67hw-j2cq · Exploit
• https://osv.dev/vulnerability/GHSA-hmgr-67hw-j2cq · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-44561 · Security Note
• https://github.com/open-webui/open-webui · Note
• https://twitter.com/kinrimini22223/status/2055866985083515331 · Twitter Post
• https://twitter.com/CVEnew/status/2055866610884182019 · Twitter Post
• https://t.me/CVEtracker/53945 · Telegram Post
• https://twitter.com/infoflowcloud/status/2055867632687984832 · Twitter Post