The Catch Popup plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'catch-popup' shortcode in all versions up to, and including, 1.4.4 due to insufficient input sanitization and output escaping on user supplied attributes. 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://wordpress.org/plugins/catch-popup/
https://plugins.trac.wordpress.org/browser/catch-popup/trunk/inc/shortcode.php