CVE-2025-55074: Mattermost Server

Low severity, CVSS 3.5. EPSS: 0.2% chance of exploitation in the next 30 days.

Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11 fail to enforce access permissions on the Agents plugin which allows other users to determine when users had read channels via channel member objects

Affected products

• Mattermost Mattermost Server: from 10.5.0, before 10.5.12 (fixed in 10.5.12); from 10.11.0, before 10.11.4 (fixed in 10.11.4)

Published 2025-11-18. Last modified 2026-06-17.