Woffice Core <= 5.4.21 - Authenticated (Subscriber+) Arbitrary File Upload

The Woffice Core plugin for WordPress, used by the Woffice Theme, is vulnerable to arbitrary file uploads due to missing file type validation in the 'saveFeaturedImage' function in all versions up to, and including, 5.4.21. 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.