CVE-2024-4198: Mattermost Server

Low severity, CVSS 2.7. EPSS: 0.5% chance of exploitation in the next 30 days.

Mattermost versions 9.6.0, 9.5.x before 9.5.3, and 8.1.x before 8.1.12 fail to fully validate role changes which allows an attacker authenticated as team admin to demote users to guest via crafted HTTP requests.

Affected products

• Mattermost Mattermost Server: from 8.1.0, before 8.1.12 (fixed in 8.1.12); from 9.5.0, before 9.5.3 (fixed in 9.5.3); version 9.6.0 only

Published 2024-04-26. Last modified 2026-06-17.