MasterStudy LMS Pro <= 4.7.0 - Authenticated (Subscriber+) Arbitrary File Upload

The MasterStudy LMS Pro plugin for WordPress is vulnerable to arbitrary file uploads due to a missing file type validation in the stm_lms_add_assignment_attachment function in all versions up to, and including, 4.7.0. This makes it possible for authenticated attackers, with Subscriber-level access and above, to upload arbitrary files on the affected site's server, which may make remote code execution possible.