CVE-2024-34029: AD/LDAP Group Members Leak

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-05-26 · updated 2026-06-17
Weakness: CWE-200

Description

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: from 8.1.0 before 8.1.13; from 9.5.0 before 9.5.4; from 9.7.0 before 9.7.2 — fixed in 8.1.13, 9.5.4, 9.7.2

How to fix

Upgrade to a fixed version: Mattermost 8.1.13, 9.5.4, 9.7.2. Check the vendor advisory for mitigations.

References

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