The User Frontend WordPress plugin before 4.3.12 does not prevent tampering with the role...

The User Frontend WordPress plugin before 4.3.12 does not prevent tampering with the role assigned by its registration form, allowing unauthenticated users to register with a higher privileged role, such as Editor.

This affects installations running a PHP build where the sodium extension is unavailable, and where a registration page has been configured. The administrator role cannot be obtained this way.