The joomsport_md_load AJAX action of the JoomSport WordPress plugin before 5.1.8, registered for both unauthenticated and unauthenticated users, unserialised user input from the shattr POST parameter, leading to a PHP Object Injection issue. Even though the plugin does not have a suitable gadget chain to exploit this, other installed plugins could, which might lead to more severe issues such as RCE