CVE-2021-37865: Mattermost

Medium severity, CVSS 5.7. EPSS: 0.9% chance of exploitation in the next 30 days.

Mattermost 6.2 and earlier fails to sufficiently process a specifically crafted GIF file when it is uploaded while drafting a post, which allows authenticated users to cause resource exhaustion while processing the file, resulting in server-side Denial of Service.

Affected products

• Mattermost Mattermost: up to and including 6.2.0

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