[German]On January 14, 2020, Microsoft released the first cumulative update (KB453555) for the Windows 10 Insider Preview Build 19041.21 (should be for the 20H1 development branch) for insiders in the slow ring. Here is some information about it.
The information about this cumulative update (KB453555) can be found in the Windows Blog. Microsoft indicates the following changes:
Security updates to 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 colleagues at deskmodder.de have listed some more details here and point out that the vulnerabilities in the CryptoAPI mentioned in the article Windows: Is a critical cryptography patch coming today? has been fixed.