CVE-2019-20863: Mattermost Server

High severity, CVSS 7.5. EPSS: 0.9% chance of exploitation in the next 30 days.

An issue was discovered in Mattermost Server before 5.13.0. Incoming webhook creation is not properly restricted.

Affected products

• Mattermost Mattermost Server: before 5.13.0 (fixed in 5.13.0)

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