The ConvertForce Popup Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the Gutenberg block's `entrance_animation` attribute in all versions up to, and including, 0.0.7. This is due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Author-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.