July 10, 2018—KB4338824 (Security-only update)

Applies to: Windows 8.1Windows Server 2012 R2

Improvements and fixes


This security update includes quality improvements. No new operating system features are being introduced in this update. Key changes include:

  • Provides protections from an additional subclass of speculative execution side-channel vulnerability known as Speculative Store Bypass (CVE-2018-3639). These protections aren't enabled by default. For Windows client (IT pro) guidance, follow the instructions in KB4073119. For Windows Server guidance, follow the instructions in KB4072698. Use this guidance document to enable mitigations for Speculative Store Bypass (CVE-2018-3639) in addition to the mitigations that have already been released for Spectre Variant 2 (CVE-2017-5715) and Meltdown (CVE-2017-5754).

  • Provides support to control usage of Indirect Branch Prediction Barrier (IBPB) on some AMD processors (CPUs) for mitigating CVE-2017-5715, Spectre Variant 2 when switching from user context to kernel context. (See AMD Architecture Guidelines for Indirect Branch Control and AMD Security Updates for more details). For Windows client (IT pro) guidance, follow the instructions in KB4073119. Use this guidance document to enable IBPB on some AMD processors (CPUs) for mitigating Spectre Variant 2 when switching from user context to kernel context.

  • Provides protections for an additional vulnerability involving side-channel speculative execution known as Lazy Floating Point (FP) State Restore (CVE-2018-3665) for 64-Bit (x64) versions of Windows.

  • Security updates to Windows apps, Windows graphics, Windows Shell, Windows datacenter networking, Windows virtualization, and Windows kernel.

For more information about the resolved security vulnerabilities, see the Security Update Guide.

Known issues in this update


Symptom Workaround
After installing this update, some devices running network monitoring workloads may receive the 0xD1 Stop error because of a race condition.

This issue is resolved in KB4345424.

Restarting the SQL Service may fail occasionally with the error, “Tcp port is already in use”. This issue is resolved in KB4345424.
When an administrator tries to stop the World Wide Web Publishing Service (W3SVC), the W3SVC remains in a "stopping" state, but cannot fully stop or be restarted. This issue is resolved in KB4345424.

 

How to get this update


This update is now available for installation through WSUS. To get the stand-alone package for this update, go to the Microsoft Update Catalog website.

File information

For a list of the files that are provided in this update, download the file information for update 4338824