PhotoPost PHP 5.0 RC3 does not fully verify that an uploaded file is an image file, which allows remote attackers to inject arbitrary Javascript by uploading non-image files with an image extension such as .gif.
https://exchange.xforce.ibmcloud.com/vulnerabilities/19679
https://euvd.enisa.europa.eu/vulnerability/EUVD-2005-0779
http://www.securityfocus.com/bid/12779