The Responsive Contact Form Builder & Lead Generation Plugin plugin for WordPress is vulnerable to unauthorized access to functionality due to a missing capability check on several functions in all versions up to, and including, 1.8.9. This makes it possible for unauthenticated attackers to invoke those functions.
https://plugins.trac.wordpress.org/changeset/3068835
https://plugins.trac.wordpress.org/browser/lead-form-builder/trunk/inc/lf-install.php#L57
https://plugins.trac.wordpress.org/browser/lead-form-builder/trunk/inc/ajax-functions.php#L674
https://plugins.trac.wordpress.org/browser/lead-form-builder/trunk/inc/ajax-functions.php#L21