CVE-2019-20843: Mattermost Server

High severity, CVSS 7.5. EPSS: 1.1% chance of exploitation in the next 30 days.

An issue was discovered in Mattermost Server before 5.18.0, 5.17.2, 5.16.4, 5.15.4, and 5.9.7. There are weak permissions for configuration files.

Affected products

• Mattermost Mattermost Server: before 5.9.7 (fixed in 5.9.7); from 5.15.0, before 5.15.4 (fixed in 5.15.4); from 5.16.0, before 5.16.4 (fixed in 5.16.4); from 5.17.0, before 5.17.2 (fixed in 5.17.2); version 5.18.0 only

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