.NET Framework covers a broad set of Windows technologies including the .NET Framework Base Class Libraries, ASP.NET Web Forms, WCF, and more.
Many products both within and outside Microsoft rely on .NET Framework. Beginning with version 4.5.2 and later, .NET Framework is defined as a component of the Windows operating system (OS). Components receive the same support as their parent products, therefore, .NET Framework 4.5.2 and later follows the lifecycle policy of the underlying Windows OS on which it is installed. The support lifecycle for various versions of Windows can be found on the Windows lifecycle fact sheet.
.NET Framework 4.8 is the latest version of .NET Framework and will continue to be distributed with future releases of Windows. As long as it is installed on a supported version of Windows, .NET Framework 4.8 will continue to also be supported.
The Support Lifecycle information for all versions of .NET Framework can be seen on the Microsoft Product Lifecycle site. ASP.NET ships external components separate from the .NET Framework. Please see ASP.NET support policy for the available options.