April 10, 2018—KB4093108 (Security-only update)

Applies to: Windows 7 Service Pack 1Windows Server 2008 R2 Service Pack 1

Improvements and fixes


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

  • Windows Update and WSUS will offer this update to applicable Windows client and server operating systems, regardless of the existence or value of the "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\QualityCompat\cadca5fe-87d3-4b96-b7fb-a231484277cc" registry setting. This change has been made to protect user data.

  • Improves reliability in the kernel, and addresses an issue that can cause applications to have unexpected memory contents on multi-processor systems.

  • Addresses a stop error that occurred when the previous month’s update was applied to a 32-bit (x86) computer with a Physical Address Extension (PAE) mode disabled.

  • Security updates to Internet Explorer, Microsoft scripting engine, Microsoft graphics component, Windows Server, Windows datacenter networking, Windows virtualization and kernel, and Windows app platform and frameworks.

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

Note: This update supercedes update 4100480, Windows kernel update for CVE-2018-1038.

Known issues in this update


Symptom Workaround

After installing KB4056897 or any other recent monthly updates, SMB servers may experience a memory leak for some scenarios. This occurs when the requested path traverses a symbolic link, mount point, or directory junction and the registry key is set to 1:  

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\LanManServer\Parameters\EnableEcp
This issue is resolved in KB4103718.
A stop error occurs on computers that don't support Streaming Single Instructions Multiple Data (SIMD) Extensions 2 (SSE2). Upgrade your machines with a processor that supports SSE2 or virtualize those machines.

How to get this update


This update is now available for installation through WSUS. To get the standalone 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 4093108.