Alex Reservations: Smart Restaurant Booking <= 2.2.3 - Authenticated (Admin+) Arbitrary File Upload

The Alex Reservations: Smart Restaurant Booking plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the /wp-json/srr/v1/app/upload/file REST endpoint in all versions up to, and including, 2.2.3. This makes it possible for authenticated attackers, with Administrator-level access and above, to upload arbitrary files on the affected site's server which may make remote code execution possible.