"Microsoft is issuing a rare out-of-band security update to supported versions of Windows today. The software update is part of a number of fixes that will protect against a newly-discovered processor bug in Intel, AMD, and ARM chipsets. Sources familiar with Microsoft’s plans tell The Verge that the company will issue a Windows update that will be automatically applied to Windows 10 machines at 5PM ET / 2PM PT today.Microsoft issues emergency Windows update for processor security bugs - The Verge
The update will also be available for older and supported versions of Windows today, but systems running operating systems like Windows 7 or Windows 8 won’t automatically be updated through Windows Update until next Tuesday. Windows 10 will be automatically updated today."
Thursday, January 04, 2018
Microsoft issues emergency Windows update for processor security bugs - The Verge
Also see Intel Memory Access Design Flaw Already Addressed by Apple in macOS 10.13.2 (MacRumors)