CVE-2019-20845: 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. It allows attackers to cause a denial of service (memory consumption) via a large Slack import.

Affected products

• Mattermost Mattermost Server: before 5.18.0 (fixed in 5.18.0)

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