KB4338853 is a critical security update for Windows 10 version 1803 (April 2018 Update) based on x86, x64 (amd64), ARM64 and Windows Server 2016 (1803) processors for x64-based systems.
As noted in the relevant Microsoft Knowledge Base article, the update includes “stability improvements for the Windows 10 Version 1803 service stack.”
Installation via Windows Update Center
Update 4338853 for the PC is installed automatically through Windows Update. To verify, go to the Settings> Update and Security menu and click Check for Updates. You do not have to restart the computer to complete the installation.
You can download the file below:x64 download update
x86 download update
ARM64 download update
Windows Server 2016 download update