CVE-2021-37860: Mattermost

Medium severity, CVSS 6.1. EPSS: 0.6% chance of exploitation in the next 30 days.

Mattermost 5.38 and earlier fails to sufficiently sanitize clipboard contents, which allows a user-assisted attacker to inject arbitrary web script in product deployments that explicitly disable the default CSP.

Affected products

• Mattermost Mattermost: up to and including 5.38

Published 2021-09-22. Last modified 2026-06-17.