The WP Cloud Plugins Use-your-Drive, Out-of-the-Box, Share-one-Drive, and Lets-Box plugins for WordPress are vulnerable to Arbitrary File Upload in all versions from 2.0 up to, and including, 3.8.3 via the download_file_to_uploads function. This is due to the import action being registered for unauthenticated users via wp_ajax_nopriv_, a missing capability check in can_import(), and the imported file's extension and contents not being validated against get_allowed_mime_types() before it is written to the uploads directory. This makes it possible for authenticated attackers, with subscriber-level access and above, to upload files that may be executable, which makes remote code execution possible.