This exploit uses the history API, which allows JavaScript to change the URL in the browser URL bar to another URL with the same origin without actually causing

This exploit uses the history API, which allows JavaScript to change the URL in the browser URL bar to another URL with the same origin without actually causing a new full page request. The same-origin policy has always been in place, because it would obviously be a huge vulnerability to allow any web page to pretend to be a different website. Changing window.location is different: it allows you to change the browser URL bar to any URL (including google.com, etc.), but it actually causes the browser to do a normal page load of the new URL, just like if the user had clicked a link to the new URL. Thus there is no spoofing vulnerability exposed by the window.location feature.