source: https://www.securityfocus.com/bid/9994/info

Multiple SQL injection, cross-site scripting and HTML injection vulnerabilities have been identified in the application, which may allow an attacker to execute arbitrary HTML or script code in a user's browser and/or influence SQL query logic to disclose sensitive information and carry out other attacks.

Photopost PHP Pro 4.6.0 and prior may be prone to these issues. Photopost PHP Pro 4.8.1 is reported vulnerable to these issues as well.

http://www.example.com/showgallery.php?ppuser=-2'%20UNION%20SELECT%200,email,
0,0,0,0,0,0%20FROM%20user%20WHERE%20userid='1&cat=500