The WP FOFT Loader plugin for WordPress is vulnerable to arbitrary file uploads due to incorrect file type validation in the 'WP_FOFT_Loader_Mimes::file_and_ext' function in all versions up to, and including, 2.1.39. This makes it possible for authenticated attackers, with Author-level access and above, to upload arbitrary files on the affected site's server which may make remote code execution possible.