Profile Builder Pro <= 3.14.5 - Unauthenticated PHP Object Injection

The Profile Builder Pro plugin for WordPress is vulnerable to PHP Object Injection in all versions up to and including 3.14.5. This is due to the use of PHP's maybe_unserialize() function on the attacker-controlled 'args' POST parameter within the wppb_request_users_pins_action_callback() AJAX handler, which lacked any nonce verification, type checking, or input validation before deserialization. Because the handler was registered with both wp_ajax_ and wp_ajax_nopriv_ hooks, it was reachable by completely unauthenticated users. This makes it possible for unauthenticated attackers to inject arbitrary PHP objects into application memory.

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: Profile Builder Pro 3.14.6 closes this, and updating the plugin is the step that ends it.

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