Umbraco CMS Authorization and Injection
2026-03-10
Privilege escalation in Umbraco CMS versions 15.3.1 through 16.5.0 and 17.x before 17.2.2 allows authenticated backoffice users with user management permissions to assign themselves elevated privileges by bypassing authorization checks on role assignments. An attacker with these permissions could gain administrative access to the CMS without proper privilege validation. No patch is currently available for affected installations.
Umbraco is an ASP.NET CMS. From 16.2.0 to versions up to 16.5.1 is affected by cross-site scripting (xss) (CVSS 6.7).
Umbraco CMS versions 14.0.0 through 16.5.0 and 17.0.0-17.2.1 contain an authorization bypass in a backoffice API endpoint that allows authenticated editors to assign domain configurations to content nodes they lack permission to access. An attacker with valid credentials could exploit this to modify domain settings on restricted content, potentially affecting content visibility or routing. The vulnerability affects Umbraco deployments without patches 16.5.1 or 17.2.2 applied.