CVE-2025-4981: Mattermost Server

Critical severity, CVSS 9.9. EPSS: 0.8% chance of exploitation in the next 30 days.

Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to sanitize filenames in the archive extractor which allows authenticated users to write files to arbitrary locations on the filesystem via uploading archives with path traversal sequences in filenames, potentially leading to remote code execution. The vulnerability impacts instances where file uploads and document search by content is enabled (FileSettings.EnableFileAttachments = true and FileSettings.ExtractContent = true). These configuration settings are enabled by default.

Affected products

• Mattermost Mattermost Server: from 9.11.0, before 9.11.16 (fixed in 9.11.16); from 10.5.0, before 10.5.6 (fixed in 10.5.6); from 10.6.0, before 10.6.6 (fixed in 10.6.6); from 10.7.0, before 10.7.3 (fixed in 10.7.3); version 10.8.0 only

Published 2025-06-20. Last modified 2026-06-17.