Applies to:
Microsoft .NET Framework 3.5 Microsoft .NET Framework 4.5.2 Microsoft .NET Framework 4.6 Microsoft .NET Framework 4.6.1 Microsoft .NET Framework 4.6.2 Microsoft .NET Framework 4.7 Microsoft .NET Framework 4.7.1 Microsoft .NET Framework 4.7.2 Microsoft .NET Framework 4.8
Important
This update is included in the Security and Quality Rollup that's dated February 9, 2021. Parts of this update were previously released in the rollup that's dated October 13, 2020.
Summary
Security Improvements
This security update addresses a denial of service vulnerability in .NET Framework. For more information please see CVE-2021-24111.
Quality Improvements
For a list of improvements that were released with this update, please see the article links in the Additional Information section of this article.
Important
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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.
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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.
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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
Known issues in this update
There is a known issue with some of the updates to Microsoft .NET Framework 4.6 and higher that released as a part of this update. For details please see the links in the Additional Information section.
Additional information about this update
The following articles contain additional information about this update as it relates to individual product versions.
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4578953 Description of the Security and Quality Rollup for .NET Framework 3.5 for Windows 8.1, RT 8.1, and Windows Server 2012 R2 (KB4578953)
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4578956 Description of the Security and Quality Rollup for .NET Framework 4.5.2 for Windows 8.1, RT 8.1, and Windows Server 2012 R2 (KB4578956)
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4601048 Description of the Security and Quality Rollup for .NET Framework 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2 for Windows 8.1, RT 8.1, and Windows Server 2012 R2 (KB4601048)
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4601058 Description of the Security and Quality Rollup for .NET Framework 4.8 for Windows 8.1, RT 8.1, and Windows Server 2012 R2 (KB4601058)
Release Channel |
Available |
Next Step |
Windows Update and Microsoft Update |
Yes |
None. This update will be downloaded and installed automatically from Windows Update. |
Microsoft Update Catalog |
Yes |
To get the standalone package for this update, go to the Microsoft Update Catalog website. |
Windows Server Update Services (WSUS) |
Yes |
This update will automatically sync with WSUS if you configure Products and Classifications as follows: Classification: Security Updates |
Information about protection and security
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Protect yourself online: Windows Security support
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Learn how we guard against cyber threats: Microsoft Security