CVE-2025-6465: Mattermost Fails to Sanitize File Names

August 21, 2025 (updated August 22, 2025)

Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 10.10.x <= 10.10.0, 10.9.x <= 10.9.3 fail to sanitize file names which allows users with file upload permission to overwrite file attachment thumbnails via path traversal in file streaming APIs.

References

github.com/advisories/GHSA-pj6f-rc94-gw53
github.com/mattermost/mattermost
mattermost.com/security-updates
nvd.nist.gov/vuln/detail/CVE-2025-6465

Code Behaviors & Features

Detect and mitigate CVE-2025-6465 with GitLab Dependency Scanning

Secure your software supply chain by verifying that all open source dependencies used in your projects contain no disclosed vulnerabilities. Learn more about Dependency Scanning →