CVE-2017-18885: Mattermost Server

Critical severity, CVSS 9.8. EPSS: 1.2% chance of exploitation in the next 30 days.

An issue was discovered in Mattermost Server before 4.3.0, 4.2.1, and 4.1.2. It allows attackers to gain privileges by accessing unintended API endpoints on a user's behalf.

Affected products

• Mattermost Mattermost Server: before 4.1.2 (fixed in 4.1.2); from 4.2.0, before 4.2.1 (fixed in 4.2.1); version 4.3.0 only

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