The Metform Elementor Contact Form Builder for WordPress is vulnerable to Information Disclosure via the 'mf_last_name' shortcode in versions up to, and including, 3.3.1. This allows authenticated attackers, with subscriber-level capabilities or above to obtain sensitive information about arbitrary form submissions, specifically the submitter's last name.
https://plugins.trac.wordpress.org/changeset/2910040/
https://plugins.trac.wordpress.org/browser/metform/trunk/base/shortcode.php?rev=2845078