GHSA-cjm8-jxpw-g43mMediumCVSS 4.3

Mattermost doesn't validate 7zip archive structure before processing

Published
May 18, 2026
Last Modified
June 1, 2026

🔗 CVE IDs covered (1)

CVE-2026-6340 →

📋 Description

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to validate 7zip archive structure before processing which allows an authenticated attacker to cause server memory exhaustion and denial of service via uploading a specially crafted 7zip file with excessive folder declarations.. Mattermost Advisory ID: MMSA-2026-00573

🎯 Affected products5

  • go/github.com/mattermost/mattermost/server/v8:>= 11.5.0, < 11.5.2
  • go/github.com/mattermost/mattermost/server/v8:>= 10.11.0, < 10.11.14
  • go/github.com/mattermost/mattermost/server/v8:>= 11.4.0, < 11.4.4
  • go/github.com/mattermost/mattermost/server/v8:< 8.0.0-20260325191733-fb11968f8798
  • go/github.com/mattermost/mattermost-server:< 5.3.2-0.20260325191733-fb11968f8798

🔗 References (4)