CVE-2026-2462: Mattermost Server

Medium severity, CVSS 6.6. EPSS: 0.3% chance of exploitation in the next 30 days.

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to restrict plugin installation on CI test instances with default admin credentials which allows an unauthenticated attacker to achieve remote code execution and exfiltrate sensitive configuration data including AWS and SMTP credentials via uploading a malicious plugin after changing the import directory. Mattermost Advisory ID: MMSA-2025-00528

Affected products

• Mattermost Mattermost Server: from 10.11.0, before 10.11.11 (fixed in 10.11.11); from 11.2.0, before 11.2.3 (fixed in 11.2.3); from 11.3.0, before 11.3.1 (fixed in 11.3.1)

Published 2026-03-16. Last modified 2026-06-17.