Microsoft Windows Security Updates February 2021 overview

Microsoft released security updates for all supported versions of the company's Windows operating system on the February 2021 patch day. Updates have been released for other company products such as Microsoft Office as well.

Our guide provides system administrators and home users with information on the released updates. It provides details on the released updates, links to official support articles, as well as information about known issues and download options.

Click here to open the January 2021 Patch overview if you missed it or want to revisit it.

The Microsoft Windows Security Updates February 2021

Download the following Excel spreadsheet that lists the released security updates for Microsoft's Windows operating system and other company products. Click on the following link to start the download: Security Updates 2021-02-10-065857am

Executive Summary

• Microsoft released security updates for all supported client and server Windows products.
• Microsoft released security updates for many other company products as well including Microsoft Office, Visual Studio, SysInternals, Skype for Business, DirectX, PowerShell, or Azure IoT.
• The legacy version of Microsoft Edge will run out of support after next month's Patch Tuesday. It will be replaced by the Chromium-based Edge browser.

Operating System Distribution

• Windows 7  (extended support only): 5 vulnerabilities: 2 critical and 3 important
  • CVE-2021-1722 -- Windows Fax Service Remote Code Execution Vulnerability
  • CVE-2021-24094 -- Windows TCP/IP Remote Code Execution Vulnerability
• Windows 8.1: 6 vulnerabilities: 2 rated critical and 4 rated important
  • CVE-2021-1722 -- Windows Fax Service Remote Code Execution Vulnerability
  • CVE-2021-24094 -- Windows TCP/IP Remote Code Execution Vulnerability
• Windows 10 version 1809: 11 vulnerabilities: 2 critical and 11 important
  • CVE-2021-1722 -- Windows Fax Service Remote Code Execution Vulnerability
  • CVE-2021-24081 -- Microsoft Windows Codecs Library Remote Code Execution Vulnerability
• Windows 10 version 1903 and 1909: 10 vulnerabilities: 3 critical and 7 important
  • CVE-2021-24081 -- Microsoft Windows Codecs Library Remote Code Execution Vulnerability
  • CVE-2021-1722 -- Windows Fax Service Remote Code Execution Vulnerability
  • CVE-2021-24094 -- Windows TCP/IP Remote Code Execution Vulnerability
• Windows 10 version 2004 and 20H2: 12 vulnerabilities, 2 critical, 10 important
  • CVE-2021-1722 -- Windows Fax Service Remote Code Execution Vulnerability
  • CVE-2021-24081 -- Microsoft Windows Codecs Library Remote Code Execution Vulnerability

Windows Server products

• Windows Server 2008 R2 (extended support only): 5 vulnerabilities: 2 critical and 3 important
  • CVE-2021-1722 -- Windows Fax Service Remote Code Execution Vulnerability
  • CVE-2021-24094 -- Windows TCP/IP Remote Code Execution Vulnerability
• Windows Server 2012 R2: 6 vulnerabilities: 2 critical and 4 important
  • CVE-2021-1722 -- Windows Fax Service Remote Code Execution Vulnerability
  • CVE-2021-24094 -- Windows TCP/IP Remote Code Execution Vulnerability
• Windows Server 2016: 9 vulnerabilities: 3 critical and 6 important.
  • CVE-2021-24081 -- Microsoft Windows Codecs Library Remote Code Execution Vulnerability
  • CVE-2021-1722 -- Windows Fax Service Remote Code Execution Vulnerability
  • CVE-2021-24094 -- Windows TCP/IP Remote Code Execution Vulnerability
• Windows Server 2019: 11 vulnerabilities: 3  critical and 8 important.
  • CVE-2021-24081 -- Microsoft Windows Codecs Library Remote Code Execution Vulnerability
  • CVE-2021-1722 -- Windows Fax Service Remote Code Execution Vulnerability
  • CVE-2021-24094 -- Windows TCP/IP Remote Code Execution Vulnerability

Windows Security Updates

Windows 7 SP1 and Windows Server 2008 R2

• Monthly Rollup: KB4601347 
• Security-only: KB4601363 

Updates and improvements:

• Historical daylight saving time updates and corrections for the Palestinian Authority.
• Addressed an issue with German translations of Central European Time.
• Security updates.

Windows 8.1 and Windows Server 2012 R2

• Monthly Rollup:  KB4601384 
• Security-only: KB4601349 

Updates and improvements:

• Historical daylight saving time updates and corrections for the Palestinian Authority.
• Addressed an issue with German translations of Central European Time.
• Security updates.

Windows 10 version 1809

• Support Page: KB4601345

Updates and improvements:

• Fixed a "possible elevation of privilege vulnerability in the win32k component".
• Security updates.

Windows 10 version 1903 and 1909

• Support Page: KB4601315 

Updates and improvements:

• Fixed a "possible elevation of privilege vulnerability in the win32k component".
• Security updates.

Windows 10 version 2004 and 20H2

• Support Page: KB4601319 

Updates and improvements:

• Fixed a "possible elevation of privilege vulnerability in the win32k component".
• Fixes an issue that could damage the file system after running chkdsk /f.
• Security updates.

Other security updates

KB4601348 -- 2021-02 Security Monthly Quality Rollup for Windows Embedded 8 Standard and Windows Server 2012

KB4601366 -- 2021-02 Security Only Quality Update for Windows Server 2008

KB4601331 -- 2021-02 Cumulative Update for Windows 10 Version 1507

KB4601330 -- 2021-02 Cumulative Update for Windows 10 Version 1703

KB4601354 -- 2021-02 Cumulative Update for Windows 10 Version 1803

.NET

KB4600944 -- 2021-02 Security and Quality Rollup for .NET Framework 4.8 for Windows Embedded Standard 7, Windows 7, and Windows Server 2008 R2

KB4600945 -- 2021-02 Security and Quality Rollup for .NET Framework 4.6 for Windows Embedded Standard 7, Windows 7, Windows Server 2008 R2, and Windows Server 2008

KB4601048 -- 2021-02 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 and Windows Server 2012 R2

KB4600957 -- 2021-02 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 Embedded 8 Standard and Windows Server 2012

KB4601057 -- 2021-02 Security and Quality Rollup for .NET Framework 4.8 for Windows Embedded 8 Standard and Windows Server 2012

KB4601058 -- 2021-02 Security and Quality Rollup for .NET Framework 4.8 for Windows 8.1 and Windows Server 2012 R2

KB4601089 -- 2021-02 Security Only Update for .NET Framework 4.8 for Windows Embedded Standard 7, Windows 7, and Windows Server 2008 R2

KB4601090 -- 2021-02 Security Only Update for .NET Framework 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2 for Windows Embedded Standard 7, Windows 7, Windows Server 2008 R2, and Windows Server 2008

KB4601091 -- 2021-02 Security Only Update for .NET Framework 4.8 for Windows Embedded 8 Standard and Windows Server 2012

KB4601092 -- 2021-02 Security Only Update for .NET Framework 4.8 for Windows 8.1 and Windows Server 2012 R2

KB4601093 -- 2021-02 Security Only Update for .NET Framework 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2 for Windows Embedded 8 Standard and Windows Server 2012

KB4601094 -- 2021-02 Security Only Update for .NET Framework 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2 for Windows 8.1 and Windows Server 2012 R2

KB4602958 -- 2021-02 Security Only Update for .NET Framework 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8 for Windows Embedded Standard 7, Windows 7, and Windows Server 2008 R2

KB4602959 -- 2021-02 Security Only Update for .NET Framework 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8 for Windows Embedded 8 Standard and Windows Server 2012

KB4602960 -- 2021-02 Security Only Update for .NET Framework 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

KB4602961 -- 2021-02 Security Only Update for .NET Framework 4.6 for Windows Server 2008

KB4603002 -- 2021-02 Security and Quality Rollup for .NET Framework 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8 for Windows Embedded Standard 7, Windows 7, and Windows Server 2008 R2

KB4603003 -- 2021-02 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 Embedded 8 Standard and Windows Server 2012

KB4603004 -- 2021-02 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 and Windows Server 2012 R2

KB4603005 -- 2021-02 Security and Quality Rollup for .NET Framework 2.0, 3.0, 4.5.2, 4.6 for Windows Server 2008

KB4601050 -- 2021-02 Cumulative Update for .NET Framework 3.5 and 4.8 for Windows Server, version 20H2, Windows 10 Version 20H2, Windows Server, version 2004, and Windows 10 Version 2004

KB4601051 -- 2021-02 Cumulative Update for .NET Framework 4.8 for Windows Server 2016 and Windows 10 Version 1607

KB4601052 -- 2021-02 Cumulative Update for .NET Framework 4.8 for Windows 10 Version 1703

KB4601054 -- 2021-02 Cumulative Update for .NET Framework 4.8 for Windows 10 Version 1803 and Windows Server 2016 (1803)

KB4601055 -- 2021-02 Cumulative Update for .NET Framework 3.5 and 4.8 for Windows Server 2019 and Windows 10 Version 1809

KB4601056 -- 2021-02 Cumulative Update for .NET Framework 3.5 and 4.8 for Windows Server, version 1909 and Windows 10 Version 1909

KB4601060 -- 2021-02 Cumulative Update for .NET Framework 3.5 and 4.7.2 for Windows Server 2019 and Windows 10 Version 1809

KB4601887 -- 2021-02 Cumulative Update for .NET Framework 3.5 and 4.7.2 for Windows Server 2019 and Windows 10 Version 1809

Known Issues

Windows 7 SP1 and Server 2008 R2

• Updates may fail if the machine does not support ESU.
• Certain operations may fail on cluster shared volumes with the error "STATUS_BAD_IMPERSONATION_LEVEL (0xC00000A5)".
  • Microsoft suggests to perform the operations from a process that has administrator privileges', or from a node that does not have CSV ownership.

Windows 8.1 and Server 2012 R2

• Certain operations may fail on cluster shared volumes with the error "STATUS_BAD_IMPERSONATION_LEVEL (0xC00000A5)".
  • Microsoft suggests to perform the operations from a process that has administrator privileges', or from a node that does not have CSV ownership.

Windows 10 version 1809

• Devices with Asian language packs installed may receive error "0x800f0982 - PSFX_E_MATCHING_COMPONENT_NOT_FOUND."
  • Microsoft recommends uninstalling and re-installing recently added language packs, and installing the latest updates for the operating system. If that does not help, Microsoft suggests to reset the PC.

Windows 10 version 1903 and 1909

• System and user certificates may be lost when updating to a later version of Windows 10
  • Microsoft recommends going back to the previously installed version of Windows.
• Games may not start or throw errors when using Discord's overlay while playing games.
  • The issue is fixed in the latest Discord version.

Windows 10 version 2004 and 20H2

• System and user certificates may be lost when updating to a later version of Windows 10
  • Microsoft recommends going back to the previously installed version of Windows.
• The correct Furigana characters may not be displayed when using the Microsoft Japanese Input Method Editor.
  • Microsoft is working on a resolution.
• Games may not start or throw errors when using Discord's overlay while playing games.
  • The issue is fixed in the latest Discord version.

Security advisories and updates

ADV 990001 -- Latest Servicing Stack Updates

Non-security related updates

KB890830 -- Windows Malicious Software Removal Tool

Microsoft Office Updates

You find Office update information here.

How to download and install the February 2021 security updates

Most home devices running Windows will receive the security updates automatically thanks to the built-in automatic updating functionality of the operating system. Updates are also provided as direct downloads and via management systems such as WSUS.

Note: we recommend that you back up the system and important date before the installation of updates. Windows' own recovery functionality is not 100% reliable and it is always better to have an independent backup that you can restore should things turn out wrong during or after the installation of updates.

To run a manual update check, do the following:

1. Select Start, type Windows Update and load the Windows Update item that is displayed.
2. Select check for updates to run a manual check for updates.

Direct update downloads

Below are resource pages with direct download links, if you prefer to download the updates to install them manually.

Windows 7 and Server 2008 R2

• KB4601347 -- 2021-02 Security Monthly Quality Rollup for Windows 7
• KB4601363 -- 2021-02 Security Only Quality Update for Windows 7

Windows 8.1 and Windows Server 2012 R2

• KB4601384 -- 2021-02 Security Monthly Quality Rollup for Windows 8.1
• KB4601349 -- 2021-02 Security Only Quality Update for Windows 8.1

Windows 10 (version 1809)

• KB4601345 -- 2021-02 Cumulative Update for Windows 10 Version 1809

Windows 10 (version 1903)

• KB4601315 -- 2021-02 Cumulative Update for Windows 10 Version 1903

Windows 10 (version 1909)

• KB4601315 -- 2021-02 Cumulative Update for Windows 10 Version 1909

Windows 10 (version 2004)

• KB4601319 -- 2021-02 Cumulative Update for Windows 10 Version 2004

Windows 10 (version 20H2)

• KB4601319  -- 2021-02 Cumulative Update for Windows 10 Version  20H2

Additional resources

• February 2021 Security Updates release notes
• List of software updates for Microsoft products
• List of the latest Windows Updates and Services Packs
• Security Updates Guide
• Microsoft Update Catalog site
• Our in-depth Windows update guide
• How to install optional updates on Windows 10
• Windows 10 Update History
• Windows 8.1 Update History
• Windows 7 Update History

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