CVE-2024-36255: Mattermost Server

Medium severity, CVSS 5.7. EPSS: 0.2% chance of exploitation in the next 30 days.

Mattermost versions 9.5.x <= 9.5.3, 9.6.x <= 9.6.1 and 8.1.x <= 8.1.12 fail to perform proper input validation on post actions which allows an attacker to run a playbook checklist task command as another user via creating and sharing a deceptive post action that unexpectedly runs a slash command in some arbitrary channel.

Affected products

• Mattermost Mattermost Server: from 8.1.0, before 8.1.13 (fixed in 8.1.13); from 9.5.0, before 9.5.4 (fixed in 9.5.4); from 9.6.0, before 9.6.2 (fixed in 9.6.2)

Published 2024-05-26. Last modified 2026-06-17.