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, 2024.1 due to the plugin allowing users to include JS files from external sources through the additional_js attribute. This makes it possible for authenticated attackers with contributor-level and above permissions to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.