CVE-2019-20851: Mattermost

Critical severity, CVSS 9.1. EPSS: 1.4% chance of exploitation in the next 30 days.

An issue was discovered in Mattermost Mobile Apps before 1.26.0. An attacker can use directory traversal with the Video Preview feature to overwrite arbitrary files on a device.

Affected products

• Mattermost Mattermost: before 1.26.0 (fixed in 1.26.0)

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