source: http://www.securityfocus.com/bid/13261/info

CityPost Simple PHP Upload is affected by a cross-site scripting vulnerability. This issue is due to a failure in the application to properly sanitize user-supplied input to the 'simple-upload-53.php' script.

An attacker may leverage this issue to have arbitrary script code executed in the browser of an unsuspecting user. This may facilitate the theft of cookie-based authentication credentials as well as other attacks. 

http://www.example.com/simple-upload-53.php?message=[XSS]