The Contact Form by Bit Form: Multi Step Form, Calculation Contact Form, Payment Contact Form & Custom Contact Form builder plugin for WordPress is vulnerable to arbitrary file read in all versions up to, and including, 2.15.2 due to improper input validation within the iconUpload function. This makes it possible for authenticated attackers, with Administrator-level access and above, to leverage a PHP filter chain attack and read the contents of arbitrary files on the server, which can contain sensitive information.
https://wordpress.org/plugins/bit-form/#developers
https://plugins.trac.wordpress.org/changeset/3165686/bit-form/trunk/includes/Admin/AdminAjax.php
https://plugins.trac.wordpress.org/changeset/3165686/
https://plugins.trac.wordpress.org/browser/bit-form/trunk/includes/Admin/AdminAjax.php#L1210