GHSA-mh4x-rmrx-3hp4MediumCVSS 6.5

Mattermost has session spoofing due to lack of single-use consumption of guest magic link tokens enforcement

Published
April 17, 2026
Last Modified
April 28, 2026

🔗 CVE IDs covered (1)

CVE-2026-3590 →

📋 Description

Mattermost versions 10.11.x <= 10.11.12, 11.5.x <= 11.5.0, 11.4.x <= 11.4.2, 11.3.x <= 11.3.2 fail to enforce atomic single-use consumption of guest magic link tokens, which allows an attacker with access to a valid magic link to establish multiple independent authenticated sessions via concurrent requests. Mattermost Advisory ID: MMSA-2026-00624.

🎯 Affected products5

  • go/github.com/mattermost/mattermost/server/v8:>= 8.0.0-20250721062209-4952acea88ce, < 8.0.0-20250723052842-4cb8d8940332
  • go/github.com/mattermost/mattermost-server:>= 10.11.0-rc1, < 10.11.13
  • go/github.com/mattermost/mattermost-server:= 11.5.0-rc1
  • go/github.com/mattermost/mattermost-server:>= 11.4.0-rc1, < 11.4.3
  • go/github.com/mattermost/mattermost-server:>= 11.3.0-rc1, < 11.3.3

🔗 References (3)