CVE-2017-18909: Mattermost Server

High severity, CVSS 7.5. EPSS: 0.7% chance of exploitation in the next 30 days.

An issue was discovered in Mattermost Server before 3.9.0 when SAML is used. Encryption and signature verification are not mandatory.

Affected products

• Mattermost Mattermost Server: before 3.9.0 (fixed in 3.9.0)

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