A Microsoft Security out of band release for Windows Update has been just issued.  It is designed to fix recent Intel Spectre issues

https://www.pcworld.com/article/3251825/security/microsofts-issues-another-emergency-windows-patch-to-pull-intels-buggy-spectre-fix.html

 

If you’ve noticed any unexpected reboots or PC instability as a result of the recent Spectre patches, there’s a solution: Microsoft has issued an emergency Windows patch that rolls back the recent Spectre mitigations.

Confused? It’s a bit complicated. After the intial Spectre and Meltdown vulnerabilites were disclosed, both Intel and Microsoft hustled out patches to mitigate the problem. Unfortunately, Intel’s latest microcode updates—and the BIOS updates from PC makers based upon them—were themselves buggy, causing instability, reboots, and data loss in some PCs.

Microsoft’s latest patch (KB4078130) allows people with affected systems to download the patch via the Microsoft Update Catalog, which disables the mitigations for the “Spectre variant 2.”