Privilege Escalation Vulnerability in Mattermost by Mattermost
CVE-2026-6739

6.7MEDIUM

Key Information:

Vendor

Mattermost
Status
Mattermost
Vendor
CVE Published:
12 June 2026

What is CVE-2026-6739?

A vulnerability in Mattermost allows authenticated users with delegated user-management permissions to escalate their privileges. This occurs due to a failure to enforce necessary system-level permissions when altering the built-in role permissions via the role patch API. Specifically, versions 11.6.x up to 11.6.1, 11.5.x up to 11.5.4, and 10.11.x up to 10.11.16 are impacted, exposing users to potential unauthorized access and manipulation of critical role settings.

Affected Version(s)

Mattermost 11.6.0 <= 11.6.1

Mattermost 11.5.0 <= 11.5.4

Mattermost 10.11.0 <= 10.11.15

References

https://mattermost.com/security-updates
vendor-advisory

CVSS V3.1

Score:
6.7
Severity:
MEDIUM
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
High
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

NeganSpl01t
.