The Gallery : FooGallery plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'custom_settings' Shortcode Attribute in all versions up to, and including, 3.3.2 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.
https://plugins.trac.wordpress.org/changeset/3680965/foogallery
https://plugins.trac.wordpress.org/browser/foogallery/trunk/includes/functions.php#L301
https://plugins.trac.wordpress.org/browser/foogallery/trunk/assets/js/foogallery.4cc6f51b.js#L8048
https://plugins.trac.wordpress.org/browser/foogallery/trunk/assets/js/foogallery.4cc6f51b.js#L7367
https://plugins.trac.wordpress.org/browser/foogallery/trunk/assets/js/foogallery.4cc6f51b.js#L6599
https://plugins.trac.wordpress.org/browser/foogallery/tags/3.2.6/includes/functions.php#L301