Security researcher Mariusz Mlynski , via TippingPoint"s Pwn2Own contest, reported that it is possible for untrusted web content to load a chrome-privileged page by getting JavaScript-implemented WebIDL to call window.open() . A second bug allowed the bypassing of the popup-blocker without user interaction. Combined these two bugs allow an attacker to load a JavaScript URL that is executed with the full privileges of the browser, which allows arbitrary code execution.