CVE-2024-4183: Mattermost Server

Medium severity, CVSS 6.5. EPSS: 0.6% chance of exploitation in the next 30 days.

Mattermost versions 8.1.x before 8.1.12, 9.6.x before 9.6.1, 9.5.x before 9.5.3, 9.4.x before 9.4.5 fail to limit the number of active sessions, which allows an authenticated attacker to crash the server via repeated requests to the getSessions API after flooding the sessions table.

Affected products

• Mattermost Mattermost Server: from 8.1.0, before 8.1.12 (fixed in 8.1.12); from 9.4.0, before 9.4.5 (fixed in 9.4.5); from 9.5.0, before 9.5.3 (fixed in 9.5.3); from 9.6.0, before 9.6.1 (fixed in 9.6.1)

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