Microsoft revealed a nasty bug in its Internet Explorer browser on Saturday. Today, the U.S. government issued an advisory warning people not to use Microsoft’s browser. The bug, Microsoft reported, “may corrupt memory in a way that could allow an attacker to execute arbitrary code in the context of the current user within Internet Explorer.” In case that’s not clear enough: It means a hacker could run any code they want on your system, simply by getting you to visit a malicious website.