Almost two months ago when the news about Meltdown and Spectre first appeared in the mainstream media, the whole world was in a great shock. These vulnerabilities have been present in some of the Intel processors for decades. In order to protect your systems, you have to update both the operating system as well as the microcode for the processors.
Microsoft has released some of the patches while Intel is still working on the microcode updates for the processors. You can find whether any microcode updates are available for your processor by visiting the Microsoft website at https://support.microsoft.com/en-us/help/4090007/intel-microcode-updates.
A few days ago, Intel has also announced about their schedule of upcoming microcode updates (MCU) for various Intel processors. You can check whether an update for your processor is available or planned by Intel by downloading the PDF file from https://newsroom.intel.com/wp-content/uploads/sites/11/2018/03/microcode-update-guidance.pdf.
But both of the above links list the microcode updates by the CPUID. How can you find the CPUID for your Intel processor? You can use the freeware InSpectre tool both to detect whether you are protected against the vulnerabilities and to find out your CPUID. As you run this tool, it will show protection status for Meltdown, protection status for Spectre and your Intel processor’s CPUID. You can note down the CPUID and use this to find information about available/planned MCU from Microsoft or Intel website links given above.
Apart from all this, the tool includes a wealth of information about these vulnerabilities and how you can protect your Windows PC against them. For example, it tells you that only Windows 10 version 1709 can receive the microcode updates and from where you can find these updates.
InSpectre tool is updated very often to include the latest information about the Meltdown or Spectre vulnerabilities. The recent version includes the Intel CPUID information from the PDF document linked above.
You can download InSpectre tool from https://www.grc.com/inspectre.htm.