GHSA-g7fp-cqj5-x8hfMediumCVSS 5.4

Mattermost has an Incorrect Authorization issue

Published
March 26, 2026
Last Modified
March 31, 2026

🔗 CVE IDs covered (1)

CVE-2026-4274 →

📋 Description

Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to restrict team-level access when processing membership sync from a remote cluster, which allows a malicious remote cluster to grant a user access to an entire private team instead of only the shared channel via sending crafted membership sync messages that trigger team membership assignment. Mattermost Advisory ID: MMSA-2026-00574

🎯 Affected products5

  • go/github.com/mattermost/mattermost/server/v8:>= 11.4.0-rc1, < 11.4.1
  • go/github.com/mattermost/mattermost/server/v8:>= 11.3.0-rc1, < 11.3.2
  • go/github.com/mattermost/mattermost/server/v8:>= 11.2.0-rc1, < 11.2.3
  • go/github.com/mattermost/mattermost/server/v8:>= 10.11.0-rc1, < 10.11.1
  • go/github.com/mattermost/mattermost/server/v8:>= 8.0.0-20260105080200-d27a2195068d, < 8.0.0-20260217110922-b7d4a1f1f59b

🔗 References (3)