Windows 10: Micro code updates (May 21, 2018)

[German]Microsoft has released several microcode updates for the still supported Windows 10 builds in revised form. These are the updates KB4090007, KB4091663 KB4091664 and KB4091666.


In the blog article Windows 10: Microcode updates KB4090007, KB4091663, KB4091664, KB4091666, KB4078407 I wrote about new microcode updates for various Windows 10 builds at the end of April 2018. 

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A new V4 vulnerability

On May 21, 2018 Microsoft (in the advisories ADV180012 and ADV180013) and Intel (here) revealed a new Spectre V4 vulnerability in Intel processors. I had posted in the blog post Google and Microsoft unveil Spectre V4 CPU vulnerability, and Intel had announced new microcode updates.

Refreshing Windows 10 Microcode Updates

Colleagues at have noticed that Microsoft has updated the downloads in the Microsoft Update Catalog for various microcode updates as of May 21, 2018. Microsoft is silent about whether the fixes for the Spectre V4 vulnerability mentioned above have already been integrated into the microcode update.

However, the release date May 21, 2018 for the packages in the Microsoft Update Catalog and the announcement of the details of the ADV180012 and ADV180013 vulnerabilities suggest this – but you can't be sure. Microsoft first wants to provide firmware updates for its Surface devices (see).

The KB articles linked below describe which CPUs are supported by the microcode.


  • KB4090007 for Windows 10 Version 1709 und Windows Server 2016 Version 1709
  • KB4091663 for Windows 10 Version 1703
  • KB4091664 for Windows 10 Version 1607 und Windows Server 2016
  • KB4091666 for Windows 10 Version 1507 (RTM)

The articles are still in an old revision of April 26, 2018 and must be downloaded from the Microsoft Update Catalog using the download links below.

These are microcode updates with a release date of May 21, 2018. For Windows 10 version 1511 (November 2015 update) there are probably no microcode updates available. And also Windows 10 version 1803 (April update) has not received a newer microcode update. The last microcode update KB4100347 (see Windows 10 V1803: Microcode update KB4100347 (05/15/2018)) from the Microsoft Update Catalog has the release date 17.5.2018, the KB article was last revised on May 19, 2018. 

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One Response to Windows 10: Micro code updates (May 21, 2018)

  1. EP says:

    The revised KB4090007, KB4091663, KB4091664 & KB4091666 updates now include updated Intel Microcodes for Ivy Bridge & Sandy Bridge processors.

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