GHSA-jqgv-39mg-7c2rMediumCVSS 6.4

Mattermost doesn't authenticate Atlassian Connect installed callbacks, allowing a remote unauthenticated attacker to inject a rogue sharedSecret

Published
June 22, 2026
Last Modified
September 15, 2026

🔗 CVE IDs covered (1)

CVE-2026-6673 →

📋 Description

Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to authenticate Atlassian Connect installed callbacks, allowing a remote unauthenticated attacker to inject a rogue sharedSecret and disrupt the Jira integration via POST to /ac/installed during the pending-install window.. Mattermost Advisory ID: MMSA-2026-00654

🎯 Affected products4

  • go/github.com/mattermost/mattermost-server:>= 11.7.0, < 11.7.1
  • go/github.com/mattermost/mattermost-server:>= 11.6.0, < 11.6.3
  • go/github.com/mattermost/mattermost-server:>= 11.5.0, < 11.5.6
  • go/github.com/mattermost/mattermost-server:>= 10.11.0, < 10.11.18

🔗 References (3)