KB4571756 is a cumulative update for Windows 10 v2004. Here are the direct download links for the KB4571756 update offline installer.
This patch Tuesday, Microsoft released another cumulative update with a fair list of fixes and improvements for Windows 10 v2004 users. Unlike the optional update released a few days back, this is a mandatory update. This means that it will be installed automatically via the Windows Update channel. Along with the regular fixes and improvements, the update also includes basic security improvements to input devices and Windows basic operations.
Some of the fixes and improvements in the update include but not limited to issues with privilege escalation in windowmanagement.dll file, security updates for various Windows components, security patches for user proxies.
Like always, the update can be directly installed from the Windows Update page in the Settings. Open the Settings app, go to "Update & Security → Windows Update" and click the "Check for updates" button. If the update is available for your machine, it will be downloaded and installed automatically. To install the KB4571756 update in an offline Windows 10 v2004 machine or if the Windows update is causing problems, use the direct links given below to download KB4571756 update offline installer.
Download KB4571756 Offline Installer
To make things easier for you, I found the direct download links for KB4571756 for both Windows 10 32-bit and 64-bit systems. Depending on your system type, download the update using the below links and install it like any other Windows software. After installing, restart the system and you are good to go.
KB4571756 x86 (32-bit) offline installer (download size: 113.5 MB)
KB4571756 x64 (64-bit) offline installer (download size: 337.3 MB)
If the above links didn't work for any reason, go to the Microsoft update catalog website to find the appropriate links. All you have to do is click on the Download button next to the appropriate version.
KB4571756 Change Log
Here's the full changelog of the KB4571756 update.
Addresses an issue with a possible elevation of privilege in windowmanagement.dll.
Addresses a security vulnerability issue with user proxies and HTTP-based intranet servers. After installing this update, HTTP-based intranet servers cannot leverage a user proxy by default to detect updates. Scans using these servers will fail if the clients do not have a configured system proxy. If you must leverage a user proxy, you must configure the behavior using the Windows Update policy “Allow user proxy to be used as a fallback if detection using system proxy fails.” This change does not affect customers who secure their Windows Server Update Services (WSUS) servers with the Transport Layer Security (TLS) or Secure Sockets Layer (SSL) protocols. For more information, see Improving security for devices receiving updates via WSUS.
Security updates to Windows App Platform and Frameworks, Microsoft Graphics Component, Windows Input and Composition, Windows Media, Windows Shell, Windows Cloud Infrastructure, Windows Fundamentals, Windows Management, Windows Kernel, Windows Virtualization, Windows Storage and Filesystems, the Microsoft Scripting Engine, and the Microsoft JET Database Engine.
That is it.