Microsoft .NET Framework 3.5
An information disclosure vulnerability exists when the .NET Framework improperly handles objects in memory. An attacker who successfully exploited the vulnerability could disclose contents of an affected system's memory. To exploit the vulnerability, an authenticated attacker would need to run a specially crafted application. The update addresses the vulnerability by correcting how the .NET Framework handles objects in memory.
To learn more about the vulnerabilities, go to the following Common Vulnerabilities and Exposures (CVE).
- 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
- 4586085 Description of the Security and Quality Rollup 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, RT 8.1, and Windows Server 2012 R2 (KB4586085)
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 standalone package for this update, go to the Microsoft Update Catalog website.
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. You must install the ActiveX control to continue.
- After the ActiveX control is installed, you see the Microsoft Update Catalog screen. Type 4586085 into 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 require, 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:
20201013 Security update deployment information: October 13, 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.
Update replacement information
This update replaces previously released updates 4579979.
The English (United States) version of this software update installs files that have the attributes that are listed in the following tables.
Windows 8.1 and Windows Server 2012 R2 file information
The MANIFEST files (.manifest) and MUM files (.mum) that are installed are not listed.