CVE-2024-39836: Mattermost

Medium severity, CVSS 6.5. EPSS: 0.3% chance of exploitation in the next 30 days.

Mattermost versions 9.9.x <= 9.9.1, 9.5.x <= 9.5.7, 9.10.x <= 9.10.0 and 9.8.x <= 9.8.2 fail to ensure that remote/synthetic users cannot create sessions or reset passwords, which allows the munged email addresses, created by shared channels, to be used to receive email notifications and to reset passwords, when they are valid, functional emails.

Affected products

• Mattermost Mattermost: from 9.5.0, before 9.5.8 (fixed in 9.5.8); from 9.8.0, before 9.8.3 (fixed in 9.8.3); from 9.9.0, before 9.9.2 (fixed in 9.9.2); from 9.10.0, before 9.10.1 (fixed in 9.10.1)

Published 2024-08-22. Last modified 2026-06-17.