Intel Microcode Updates KB4346084, KB4346085, KB4346086, KB4346087, KB4346088 (August 20/21, 2018)

[German]Microsoft has released Intel microcode updates (KB4346084, KB4346085, KB4346086, KB4346087, KB4346088) for Windows 10 on August 20/21, 2018 (thanks to GeroH for the tip). Here is a brief overview.

Update KB4346084 for Windows 10 V1803

Update KB4346084 (Intel Microcode Update) is available for Windows 10 V1803. According to Microsoft, it addresses the following vulnerabilities:

Intel recently announced that they have completed their validations and started to release microcode for recent CPU platforms related to Spectre Variant 3a (CVE-2018-3640: "Rogue System Register Read (RSRE)"), Spectre Variant 4 (CVE-2018-3639: "Speculative Store Bypass (SSB)"), L1TF (CVE-2018-3615, CVE-2018-3620, CVE-2018-3646: "L1 Terminal Fault"). In addition to microcode updates previously released in KB4100347​ to address Spectre Variant 2 (CVE 2017-5715: "Branch Target Injection"), this update also includes microcode updates from Intel for the following CPUs.

This update applies to several Intel processors listed in the KB article. It is a standalone update for Windows 10 version 1803 (Windows 10 April 2018 update) and Windows Server version 1803 (Server Core). This update is distributed via Windows Update, WSUS, and the Microsoft Update Catalog.

Microsoft intends to offer additional microcode updates from Intel for this operating system via the KB article as soon as they are available for Microsoft. Vulnerability protection is enabled by default for Windows client systems, so no action is required.

Please make sure that protection against Spectre Variant 2 for servers is enabled via the registry settings documented in the article Windows Server guidance to protect against speculative execution side-channel vulnerabilities.

Notes: Microsoft advises: Check with your device manufacturer and Intel through their websites for microcode recommendations for your device before applying this update to your device.

Users of Windows 10 V1803 are still offered the Intel Microcode Update KB4100347. The package is listed in the Update Catalog with date 8/21/2018, the KB article specifies July 2018 as the last change date. I had described the package in May 2018 in the article Windows 10 V1803: Microcode update KB4100347 (05/15/2018).

Update KB4346085 for Windows 10 V1709

Update KB4346085 is the same Intel Microcode update as described above, but is available for Windows 10 V1709. The list of supported updates is listed in the KB article. There you will also find further details and the link to the Microsoft Update Catalog.

Update KB4346086 for Windows 10 V1703

Update KB4346086 is the same Intel Microcode update as described above, but is available for Windows 10 V1703. The list of supported updates is listed in the KB article. There you will also find further details and the link to the Microsoft Update Catalog.

Update KB4346087 for Windows 10 V1607

Update KB4346087 is the same Intel Microcode update as described above, but is available for Windows 10 V1607. The list of supported updates is listed in the KB article. There you will also find further details and the link to the Microsoft Update Catalog.

Update KB4346088 for Windows 10 V1507

Update KB4346088 is the same Intel Microcode update as described above, but is available for Windows 10 V1507 (RTM. The list of supported updates is listed in the KB article. There you will also find further details and the link to the Microsoft Update Catalog.

The list of updates can be viewed in the Microsoft Update Catalog (updates with date 8/20/2018). At KB4090007 is an overview of all supported CPUs.

Addendum: Microcode update overview

I'm slowly losing track of when and where which Microcode update from Microsoft was released for Windows. A summary of Intel microcode updates for Azure and Windows 10 can be found under KB4093836, where the updates are also listed. Maybe it'll help.