Windows is shipping new updates early this month. In the latest "Windows 10 Fall Creators Edition Update" version, they now have a pretty panel and call them "Feature Updates" rather than bug fixes, but you know what that means.
Info on the Windows Security Site [1] seems to indicate it's a fix for many of their security products. That, combined with the week-early date, make me suspect something's in the wild they don't want people to catch.
"Ask Woody" has a post at 8:30 am his time today referencing CVE-2017-11937. He promises a fuller post later on ComputerWorld.
Meanwhile, other links say this is an issue with the Windows "Malware Protection Engine"--Windows Defender.
The reason why Windows Defender isn't good enough is because it is manufactured by the same company that makes the OSes that it's supposed to protect. It is likely dependent on code in those OSes, and if there are flaws in that code, then there will be flaws in Windows Defender.
That is the explanation I give people when I am asked if they should rely on Windows Defender instead of using third-party malware protection.
Now I have actual data to back me up.
Ken Dibble www.stic-cil.org