PHPPost 1.0 - 'mail.php?user' Cross-Site Scripting

source: https://www.securityfocus.com/bid/15524/info
 
PHP-Post is prone to multiple cross-site scripting vulnerabilities because the application fails to properly sanitize user-supplied input.
 
An attacker may leverage these issues to execute arbitrary script code in the browser of an unsuspecting user in the context of the affected site. The attacker may also be able to steal cookie-based authentication credentials and launch other attacks. 

http://www.example.com/phpp/mail.php?user='%3CIFRAME%20SRC=javascript:alert(%2527XSS%2527)%3E%3C/IFRAME%3E