The FooGallery – Responsive Photo Gallery, Image Viewer, Justified, Masonry & Carousel plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the `data-caption-title` & `data-caption-description` HTML attributes in all versions up to, and including, 2.4.31 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.