Following on from a post on sla.ckers it emerges that Firefox has a vulnerability/bug that is very difficult to filter against and allows a fragmented XSS attack. This is best illustrated by the following example: {% highlight html %} test link {% endhighlight %} The conditions for the XSS working are 2 injection points. Injection point 1 must be inside an HTML comment whilst injection point 2 is inside a double quoted attributed.