https://support.microsoft.com/de-de/topic/security-only-update-for-net-framework-3-5-for-windows-server-2012-kb4552963-f00cdbc0-2f59-c02a-f84a-5228d4426a54
Security Only Update for .NET Framework 3.5 for Windows Server 2012 (KB4552963) - Microsoft-Support
Security Only Update for .NET Framework 3.5 for Windows Server 2012 (KB4552963)