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 and deletion due to insufficient file path validation in multiple functions in versions 2.0 to 2.13.9. This makes it possible for authenticated attackers, with Administrator-level access and above, to read and delete arbitrary files on the server, which can easily lead to remote code execution when the right file is deleted (such as wp-config.php).
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.