Windows users are encouraged to update their computers as soon as possible, after Microsoft pushed out a patch for an issue in Internet Explorer that lets attackers remotely run malicious code with whatever privileges the current user has.
The "Critical" vulnerability affects Internet Explorer versions 7 through 11 on Windows 7, 8, 8.1, 10 and Vista. Windows Server 2008, 2012, 2012 R2 and the Windows Server Technical Preview are all effected, but Internet Explorer runs in a "Enhanced Security Configuration" that should mitigate the effects of this problem. The "out-of-band" patch was released outside Microsoft's typical Patch Tuesday release cycle and allows users and administrators to update their computers quickly.
Microsoft Edge, the new browser included in Windows 10, isn't affected by the vulnerability. However, Microsoft's new operating system also ships with a copy of Internet Explorer 11 installed, which is why it's getting updated.