CVE-2017-18890: Mattermost Server

Medium severity, CVSS 4.3. EPSS: 0.8% 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 an attacker to create a button that, when pressed by a user, launches an API request.

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.