The Modal Popup Box – Popup Builder, Show Offers And News in Popup plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 1.5.2 via deserialization of untrusted input in the awl_modal_popup_box_shortcode function. This makes it possible for authenticated attackers, with contributor-level access and above, to inject a PHP Object. If a POP chain is present via an additional plugin or theme installed on the target system, it could allow the attacker to delete arbitrary files, retrieve sensitive data, or execute code.