Alongside the January 2020 Patch Tuesday, Microsoft is now releasing build 19041.21 as update KB4535550 for devices in the Slow ring running the latest preview of Windows 10 version 2004 (20H1).

Windows 10 build 19041.21, according to the company, doesn’t contain new feature, but it includes a patch to address an important vulnerability affecting Windows App Platform and Frameworks, Windows Input and Composition, Windows Graphics, Microsoft Scripting Engine, .NET Framework, Windows Cryptography, Windows Subsystem for Linux, Windows Peripherals, Windows Storage and Filesystems, and Windows Server.

The vulnerability is known as “Windows CryptoAPI Spoofing,” and according to its description, it could allow an “attacker to conduct man-in-the-middle attacks and decrypt confidential information on user connections to the affected software”.

Microsoft is listing the complete set of improvements, fixes, and known issues for Windows 10 Insider Preview build 19041.21 at the Windows Blog.

Download Windows 10 build 19041

Although there are no ISO files for Windows 10 build 19041.41, the update is available immediately through the Slow ring. This preview build will download and install automatically on your device, but you can always force the update from Settings > Update & security > Windows Update, and clicking the Check for updates button.

You can also check out these resources:

  • Windows 10 20H1 all the new features and changes
  • Windows 10 version release history tracker