CVE-2019-20867: Mattermost Server

Medium severity, CVSS 5.3. EPSS: 0.8% chance of exploitation in the next 30 days.

An issue was discovered in Mattermost Server before 5.11.0. An attacker can interfere with a channel's post loading via one crafted post.

Affected products

• Mattermost Mattermost Server: before 5.11.0 (fixed in 5.11.0)

Published 2020-06-19. Last modified 2026-06-17.