CVE-2021-37864: Mattermost

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

Mattermost 6.1 and earlier fails to sufficiently validate permissions while viewing archived channels, which allows authenticated users to view contents of archived channels even when this is denied by system administrators by directly accessing the APIs.

Affected products

• Mattermost Mattermost: up to and including 6.1

Published 2022-01-18. Last modified 2026-06-17.