Pixie 1.0.4 allows remote authenticated users to upload and execute arbitrary PHP code via the POST data in an admin/index.php?s=publish&x=filemanager request for a filename with a double extension, such as a .jpg.php file with Content-Type of image/jpeg.
https://www.exploit-db.com/exploits/41784/
http://rungga.blogspot.co.id/2017/04/remote-file-upload-vulnerability-in.html