CVE-2025-9079: Mattermost Server

High severity, CVSS 7.2. EPSS: 0.6% chance of exploitation in the next 30 days.

Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.1, 10.9.x <= 10.9.3 fail to validate import directory path configuration which allows admin users to execute arbitrary code via malicious plugin upload to prepackaged plugins directory

Affected products

• Mattermost Mattermost Server: from 9.11.0, before 9.11.18 (fixed in 9.11.18); from 10.5.0, before 10.5.9 (fixed in 10.5.9); from 10.8.0, before 10.8.4 (fixed in 10.8.4); from 10.9.0, before 10.9.4 (fixed in 10.9.4); from 10.10.0, before 10.10.2 (fixed in 10.10.2)

Published 2025-09-19. Last modified 2026-06-17.