CVE-2019-20880: 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 5.8.0, 5.7.2, 5.6.5, and 4.10.7. It allows attackers to cause a denial of service (memory consumption) via OpenGraph.

Affected products

• Mattermost Mattermost Server: before 4.10.7 (fixed in 4.10.7); from 5.6.0, before 5.6.5 (fixed in 5.6.5); from 5.7.0, before 5.7.2 (fixed in 5.7.2); version 5.8.0 only

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