CVE-2026-6739

EUVD-2026-36499
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
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
MattermostCNA
6.7 MEDIUM
NETWORK
LOW
HIGH
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
mattermostmattermost
11.6.0 ≤
𝑥
≤ 11.6.1
CNA
mattermostmattermost
11.5.0 ≤
𝑥
≤ 11.5.4
CNA
mattermostmattermost
10.11.0 ≤
𝑥
≤ 10.11.15
CNA
mattermostmattermost
10.11.0 ≤
𝑥
≤ 10.11.16
CNA
Common Weakness Enumeration
References
https://mattermost.com/security-updates