CVE-2026-6739

MEDIUM

Mattermost: Delegated admins could patch protected default system roles

Title source: cna
STIX 2.1

Description

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

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory
MMSA-2026-00656
https://mattermost.com/security-updates

Scores

CVSS v3 6.7
EPSS 0.0024
EPSS Percentile 14.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact total

Details

CWE
CWE-863
Status published
Products (9)
Mattermost/Mattermost 10.11.0 - 10.11.15
Mattermost/Mattermost 10.11.0 - 10.11.16
Mattermost/Mattermost 10.11.16
Mattermost/Mattermost 10.11.17
Mattermost/Mattermost 11.5.0 - 11.5.4
Mattermost/Mattermost 11.5.5
Mattermost/Mattermost 11.6.0 - 11.6.1
Mattermost/Mattermost 11.6.2
Mattermost/Mattermost 11.7.0
Published Jun 12, 2026
Tracked Since Jun 12, 2026