GHSL-2026-065: Unauthorized group assignment enables privilege escalation in Umbraco CMS
Umbraco CMS is vulnerable to an authorization bypass issue (GHSL-2026-065) that allows unauthorized users to assign users to groups, potentially leading to privilege escalation and improper access control.
Other sources
Umbraco CMS lacks authorization checks when assigning users to groups, allowing unauthorized users to escalate privileges.
— GitHub Security Lab
Affected Software
Event History
Frequently Asked Questions
What access would an attacker need to exploit this issue?
The issue involves assigning users to groups without authorization checks, so exploitation requires the ability to perform user-to-group assignment actions. The provided information does not identify the specific account role or endpoint required.
What is the security impact of successful exploitation?
An unauthorized user can assign group membership in a way that escalates privileges. The provided information does not specify which groups or privilege levels can be obtained.