CVE-2024-39807: Mattermost

Medium severity, CVSS 5.3. EPSS: 0.3% chance of exploitation in the next 30 days.

Mattermost versions 9.5.x <= 9.5.5 and 9.8.0 fail to properly sanitize the recipients of a webhook event which allows an attacker monitoring webhook events to retrieve the channel IDs of archived or restored channels.

Affected products

• Mattermost Mattermost: from 9.5.0, before 9.5.6 (fixed in 9.5.6); from 9.8.0, before 9.8.1 (fixed in 9.8.1)

Published 2024-07-03. Last modified 2026-06-17.