Improper Authorization in Mattermost Affects Role Management
CVE-2026-7387

8.8HIGH

Key Information:

Vendor

Mattermost
Status
Mattermost
Vendor
CVE Published:
12 June 2026

What is CVE-2026-7387?

An improper authorization vulnerability exists in Mattermost that allows users with group-link permissions to escalate their privileges by executing malicious API requests. This flaw affects specific versions of Mattermost, enabling unauthorized access to team or channel admin roles when the 'scheme_admin' flag is manipulated during group syncable link requests. Immediate action is advised to secure affected installations against potential exploitation.

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:
8.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

winfunc
.