Avada (Fusion) Builder <= 3.16.1 - Unauthenticated Arbitrary WordPress Action Invocation via '{action_hook}' Dynamic-Data Token in Form Field

The Avada (Fusion) Builder plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 3.16.1. This is due to the plugin not properly verifying authorization before dispatching a WordPress action hook whose name is taken from an attacker-supplied form-field value (via the notification email_message [field] placeholder and the {action_hook,...} dynamic-data token; the 3.16.1 trust gate is_content_request_supplied() only inspects $_POST['args']/$_GET['args'], never the $_POST['formData'] the public form-submit endpoint parses). This makes it possible for unauthenticated attackers to invoke arbitrary WordPress action hooks (multiple per request), causing state changes up to permanent, irreversible destruction of site content: a verified unauthenticated request permanently deleted trashed posts, pages, and comments via the core wp_scheduled_delete action. Other non-deny-listed hooks extend the impact to denial of service (e.g. wp_maybe_auto_update) and, where vulnerable third-party handlers are installed, further privileged writes. The same unauthenticated dynamic-data pipeline additionally exposes a blind arbitrary user/post-meta read; the read result is delivered only to the site owner and is not attacker-exfiltrable through the plugin's own email/response paths. Exploitation requires a published Avada form with AJAX submission and a notification whose email_message template includes an [all_fields] or explicit [field] placeholder - the default form configuration.

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: Avada (Fusion) Builder 3.16.2 closes this, and updating the plugin is the step that ends it.

• Firewall
• Scanner
• Login Security