CVE-2019-20877: Mattermost Server

Medium severity, CVSS 5.3. EPSS: 0.9% chance of exploitation in the next 30 days.

An issue was discovered in Mattermost Server before 5.9.0, 5.8.1, 5.7.3, and 4.10.8. It allows attackers to obtain sensitive information about whether someone has 2FA enabled.

Affected products

• Mattermost Mattermost Server: before 4.10.8 (fixed in 4.10.8); from 5.7.0, before 5.7.3 (fixed in 5.7.3); from 5.8.0, before 5.8.1 (fixed in 5.8.1); version 5.9.0 only

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