GHSA-mpc7-mm28-f6wqMediumCVSS 4.3

Mattermost allows authenticated guest users to enumerate user IDs outside their allowed visibility scope

Published
March 26, 2026
Last Modified
March 31, 2026

🔗 CVE IDs covered (1)

CVE-2026-3115 →

📋 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 apply view restrictions when retrieving group member IDs, which allows authenticated guest users to enumerate user IDs outside their allowed visibility scope via the group retrieval endpoint. Mattermost Advisory ID: MMSA-2026-00594.

🎯 Affected products5

  • go/github.com/mattermost/mattermost/server/v8:= 11.4.0
  • 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, < 10.11.11
  • go/github.com/mattermost/mattermost/server/v8:>= 8.0.0-20260105080200-d27a2195068d, < 8.0.0-20260217110922-b7d4a1f1f59b

🔗 References (3)