Critical Windows Security Patch released today by Microsoft ( 7-20-2015 )
Released today at 10AM PST Microsoft announced another remote exploit that could target a font driver.
You can read the security bulletin here: https://technet.microsoft.com/en-us/library/security/ms15-078.aspx
Microsoft Security Bulletin MS15-078 – Critical said that a vulnerability was found in the Microsoft Font Driver That Could Allow Remote Code Execution.
If you run Windows updates now you should see a new update available to patch this and it is encouraged to install this as soon as possible. Yes you will have to reboot, however since it’s a critical update I’d recommend patching this sooner rather than later.