CVE-2026-6739
Published:June 12, 2026
Updated:June 29, 2026
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 Packages
https://github.com/mattermost/mattermost.git (GITHUB):
Affected version(s) >=v11.6.0 <v11.6.2Fix Suggestion:
Update to version v11.6.2https://github.com/mattermost/mattermost.git (GITHUB):
Affected version(s) >=v11.5.0 <v11.5.5Fix Suggestion:
Update to version v11.5.5https://github.com/mattermost/mattermost.git (GITHUB):
Affected version(s) >=v10.11.0 <v10.11.16Fix Suggestion:
Update to version v10.11.16github.com/mattermost/mattermost (GO):
Affected version(s) >=v10.11.0 <v10.11.16Fix Suggestion:
Update to version v10.11.16github.com/mattermost/mattermost (GO):
Affected version(s) >=v11.5.0 <v11.5.5Fix Suggestion:
Update to version v11.5.5github.com/mattermost/mattermost (GO):
Affected version(s) >=v11.6.0 <v11.6.2Fix Suggestion:
Update to version v11.6.2Related Resources (1)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.6
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
HIGH
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
LOW
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.7
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
LOW
Weakness Type (CWE)
Incorrect Authorization
EPSS
Base Score:
0.26