CVE-2026-6673

Mattermost Jira plugin (CVE-2026-6673) authenticates poorly during Atlassian Connect install. Affected Mattermost versions (11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x

EUVD-2026-38249

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...