CVE-2024-34029: Mattermost Server

Medium severity, CVSS 4.3. EPSS: 0.3% chance of exploitation in the next 30 days.

Mattermost versions 9.5.x <= 9.5.3, 9.7.x <= 9.7.1 and 8.1.x <= 8.1.12 fail to perform a proper authorization check in the /api/v4/groups/<group-id>/channels/<channel-id>/link endpoint which allows a user to learn the members of an AD/LDAP group that is linked to a team by adding the group to a channel, even if the user has no access to the team.

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 9.7.0, before 9.7.2 (fixed in 9.7.2)

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