The Advanced iFrame plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'advanced_iframe' shortcode in all versions up to, and including, 2025.5 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://plugins.trac.wordpress.org/browser/advanced-iframe/trunk/advanced-iframe.php#L725