Description of the Security Only update for .NET Framework 3.5 for Windows 8.1 and Server 2012 R2 (KB 4480086)

Si applica a: .NET Framework

Summary


This security update resolves a vulnerability in Microsoft .NET Framework that may cause an information disclosure that allows bypassing Cross-origin Resource Sharing (CORS) configurations.

An attacker who successfully exploits this vulnerability could retrieve from a web application content that is usually restricted.

This security update addresses the vulnerability by enforcing CORS configuration to prevent it from being bypassed.

To learn more about this vulnerability, see Microsoft Common Vulnerabilities and Exposures CVE-2019-0545.
 

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 and Windows Server 2012 R2 require that update 2919355 is installed. We recommend that you install update 2919355 on your Windows 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.

Additional information about this security update


For more information about this security update as it relates to Windows 8.1 and Windows Server 2012 R2, see the following article in the Microsoft Knowledge Base:

4481485 Security Only updates for .NET Framework 3.5, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, and 4.7.2 for Windows 8.1 and Server 2012 R2 (KB 4481485)

How to obtain and install the update


Method 1: Microsoft Update Catalog

To get the stand-alone package for this update, go to the Microsoft Update Catalog.
 

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 4481485 in 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:

20190108 Security update deployment information: January 8, 2019

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.

Update replacement information

This update replaces update 3142026.

File information


How to obtain help and support for this security update