An issue was discovered in the AccessKeys AccessPress Anonymous Post Pro plugin through 3.1.9 for WordPress. Improper input sanitization allows the attacker to override the settings for allowed file extensions and upload file size, related to inc/cores/file-uploader.php and file-uploader/file-uploader-class.php. This allows the attacker to upload anything they want to the server, as demonstrated by an action=ap_file_upload_action&allowedExtensions[]=php request to /wp-admin/admin-ajax.php that results in a .php file upload and resultant PHP code execution.
