Security Only Update for .NET Framework 4.8 for Windows 8.1 and Windows Server 2012 R2 (KB4532951)

A remote code execution vulnerability exists when the Microsoft .NET Framework fails to validate input properly. An attacker who successfully exploited this vulnerability could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

To learn more about the vulnerabilities, go to the following Common Vulnerabilities and Exposures (CVE).

• CVE-2020-0605
• CVE-2020-0606
• CVE-2020-0646

Important

• As a reminder to advanced IT administrators, updates to .NET Framework 3.5 for Windows 8.1 and Windows Server 2012 R2 should only be applied on systems where .NET Framework 3.5 is present and enabled. Customers who attempt to pre-install updates to .NET Framework 3.5 to offline images that do not contain the .NET Framework 3.5 product enabled will expose these systems to failures to enable .NET Framework 3.5 after the systems are online. For more extensive information about deploying .NET Framework 3.5, see Microsoft .NET Framework 3.5 Deployment Considerations.
• All updates for Windows 8.1, Windows RT 8.1, and Windows Server 2012 R2 require that update KB 2919355 is installed. We recommend that you install update KB 2919355 on your Windows 8.1-based, Windows RT 8.1-based, or Windows Server 2012 R2-based computer so that you receive updates in the future.
• If you install a language pack after you install this update, you must reinstall this update. Therefore, we recommend that you install any language packs that you need before you install this update. For more information, see Add language packs to Windows.

• 4534978 Description of the Security Only Update for .NET Framework 3.5, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8 for Windows 8.1 and Windows Server 2012 R2 (KB4534978)

Method 1: Microsoft Update Catalog

To get the standalone package for this update, go to the Microsoft Update Catalog website.

Method 2: Windows Software Update Services (WSUS)

On your WSUS server, follow these steps:

1. Select Start, select Administrative Tools, and then select Microsoft Windows Server Update Services 3.0.
2. Expand ComputerName, and then select Action.
3. Select Import Updates.
4. WSUS opens a browser window in which you may be prompted to install an ActiveX control. You must install the ActiveX control to continue.
5. After the ActiveX control is installed, you see the Microsoft Update Catalog screen. Type 4534978 into the Search box, and then select Search.
6. Locate the .NET Framework packages that match the operating systems, languages, and processors in your environment. Select Add to add them to your basket.
7. After you select all the packages that you require, select View Basket.
8. To import the packages to your WSUS server, select Import.
9. After the packages are imported, select Close to return to WSUS.

The updates are now available for installation through WSUS.

Update deployment information

For deployment details for this security update, go to the following article in the Microsoft Knowledge Base:

20200114 Security update deployment information: January 14, 2020

Update removal information

Note We do not recommend that you remove any security update. To remove this update, use the Programs and Features item in Control Panel.

Update restart information

This update does not require a system restart after you apply it unless files that are being updated are locked or are being used.

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