CVE-2026-3112: Mattermost Server

Medium severity, CVSS 4.9. EPSS: 0.5% chance of exploitation in the next 30 days.

Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to validate Advanced Logging file target paths which allows system administrators to read arbitrary host files via malicious AdvancedLoggingJSON configuration in support packet generation. Mattermost Advisory ID: MMSA-2025-00562

Affected products

• Mattermost Mattermost Server: from 10.11.0, before 10.11.12 (fixed in 10.11.12); from 11.2.0, before 11.2.4 (fixed in 11.2.4); from 11.3.0, before 11.3.2 (fixed in 11.3.2); version 11.4.0 only

Published 2026-03-26. Last modified 2026-06-17.