CVE-2026-6739
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 require system-level permission when patching protected default system roles, which allows authenticated users with delegated user-management permissions to escalate privileges by altering built-in role permissions via the role patch API.. Mattermost Advisory ID: MMSA-2026-00656
- Affected products
- Mattermost
- Mattermost Mattermost Server
- < 10.11.17, 11.5.5, 11.6.2
- Fix
- Available
- CVSS 3.1
- 7.2 HIGH
- EPSS
- 0.3% (17th percentile)
- Weakness
- CWE-863
- NVD status
- Analyzed
- Published
- 2026-06-12
Fix
Update Mattermost to versions 11.7.0, 11.6.2, 11.5.5, 10.11.16, 10.11.17 or higher.
CVE-2026-6739 at NVD
No indexed exploits for CVE-2026-6739 yet
Our index is partial: it proves presence, never absence
No exploit for CVE-2026-6739 has been indexed yet. Our index is built from live traffic and upstream syncs, so this page can only say what it knows — not that no exploit exists.