The Avada (Fusion) Builder plugin for WordPress is vulnerable to Arbitrary WordPress Action Execution in all versions up to, and including, 3.15.1. This is due to the plugin's `output_action_hook()` function accepting user-controlled input to trigger any registered WordPress action hook without proper authorization checks. This makes it possible for authenticated attackers, with Subscriber-level access and above, to execute arbitrary WordPress action hooks via the Dynamic Data feature, potentially leading to privilege escalation, file inclusion, denial of service, or other security impacts depending on which action hooks are available in the WordPress installation.