Microsoft .NET Framework 3.5
This update is included in the Preview of Quality Rollup that's dated January 15, 2019.
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 the vulnerability could retrieve from a web application content that's normally restricted.
This security update addresses the vulnerability by enforcing CORS configuration to prevent its bypass.To learn more about this vulnerability, see Microsoft Common Vulnerabilities and Exposures CVE-2019-0545.
- 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.
Additional information about this update
For more information about this update as it relates to Windows 8.1, Windows RT 8.1, and Windows Server 2012 R2, see the following article in the Microsoft Knowledge Base:
4481490 January 2019 Preview of the Quality Rollups 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, RT 8.1, and Server 2012 R2 (KB 4481490)
4481484 Security and Quality Rollup 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, RT 8.1, and Server 2012 R2 (KB 4481484)
How to obtain and install the update
Method 1: Windows Update
This update is available through Windows Update. When you turn on automatic updating, this update will be downloaded and installed automatically. For more information about how to get security updates automatically, see Windows Update: FAQ.
Method 2: Microsoft Update Catalog
To get the stand-alone package for this update, go to the Microsoft Update Catalog.
Method 3: Windows Software Update Services (WSUS)
On your WSUS server, follow these steps:
- Select Start, select Administrative Tools, and then select Microsoft Windows Server Update Services 3.0.
- Expand ComputerName, and then select Action.
- Select Import Updates.
- WSUS opens a browser window in which you may be prompted to install an ActiveX control. Install the ActiveX control to continue.
- After the ActiveX control is installed, you see the Microsoft Update Catalog screen. Type 4481490 in the Search box, and then select Search.
- Locate the .NET Framework packages that match the operating systems, languages, and processors in your environment. Select Add to add them to your basket.
- After you select all the packages that you need, select View Basket.
- To import the packages to your WSUS server, select Import.
- 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 doesn't require a system restart after you apply it unless files that are being updated are locked or are being used.