GHSA-rp4v-qc77-phm4MediumCVSS 4.3

Mattermost doesn't restrict role_updated websocket event broadcasts to members of the affected team or channel

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 restrict role_updated websocket event broadcasts to members of the affected team or channel, which allows an authenticated attacker with guest-level access to observe permission scheme change notifications for private teams they are not a member of via the websocket connection. Mattermost Advisory ID: MMSA-2026-00616

🎯 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, < 8.0.0-20260504071740-9408b98025d7

🔗 References (15)