EUVD-2026-38250

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 validate channel ownership of an existing subscription before applying edits which allows an authenticated attacker to hijack subscriptions from channels they have no access to via a crafted PUT...

CVE-2026-6062

CVE-2026-6062 affects Mattermost versions 11.7.x ≤ 11.7.0, 11.6.x ≤ 11.6.2, 11.5.x ≤ 11.5.5, and 10.11.x ≤ 10.11.17. The issue is a logic flaw where the system fails to validate channel ownership of an existing subscription before applying edits, enabling an authenticated attacker to hijack subsc...

CVE-2026-6062 IDOR in Jira plugin subscription edit endpoint

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 validate channel ownership of an existing subscription before applying edits which allows an authenticated attacker to hijack subscriptions from channels they have no access to via a crafted PUT...

CVE-2025-48731 Unauthorized Subscription Edit to Confluence Space in Mattermost Confluence Plugin

Mattermost Confluence Plugin version 1.5.0 fails to check the access of the user to the Confluence space which allows attackers to edit a subscription for a Confluence space the user does not have access for via edit subscription endpoint...