The FooGallery – Responsive Photo Gallery, Image Viewer, Justified, Masonry & Carousel plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 2.4.29 via the foogallery_attachment_modal_save AJAX action due to missing validation on a user controlled key (img_id). This makes it possible for authenticated attackers, with granted access and above, to update arbitrary post and page content. This requires the Gallery Creator Role setting to be a value lower than 'Editor' for there to be any real impact.
The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.