The Bit Form builder plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in all versions up to, and including, 2.20.4. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible. For this to be exploitable, the PRO version needs to be installed and activated as well. Additionally a form with an advanced file upload element needs to be published.