The The InPost Gallery plugin for WordPress is vulnerable to arbitrary shortcode execution via the inpostgallerygetshortcodetemplate AJAX action in all versions up to, and including, 2.1.4.2. This is due to the software allowing users to execute an action that does not properly validate a value before running doshortcode. This makes it possible for authenticated attackers, with Subscriber-level access and above, to execute arbitrary shortcodes.