GHSA-8qq9-cqj8-82w4HighCVSS 7.6

Mattermost doesn't sanitize FileInfo.Name received from federated peers during shared channel file sync

Published
June 12, 2026
Last Modified
August 24, 2026

🔗 CVE IDs covered (1)

📋 Description

Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to sanitize FileInfo.Name received from federated peers during shared channel file sync, which allows an attacker who controls a federated server to write files to arbitrary locations within the target server's filestore via path traversal sequences in the filename field. Mattermost Advisory ID: MMSA-2026-00661

🎯 Affected products4

  • go/github.com/mattermost/mattermost-server:= 11.6.0
  • go/github.com/mattermost/mattermost-server:>= 11.5.0, <= 11.5.4
  • go/github.com/mattermost/mattermost-server:>= 10.11.0, <= 10.11.15
  • go/github.com/mattermost/mattermost/server/v8:>= 8.0.0-20250731163400-5b955468ea1e, < 8.0.0-20260423180926-c021eeaff8f0

🔗 References (17)