- April 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
Microsoft Windows Security Updates April 2021 overview
Microsoft released security and non-security updates, including KB5001330, for supported versions of Microsoft Windows and other company products such as Office on the April 2021 Patch Tuesday.
Our guide provides administrators and home users with information on the released updates. It links to all support pages, lists known issues and direct patch downloads, and lists all security and non-security update releases of the day.
Click here to open the March 2021 Patch Day overview in case you missed it or want to revisit it.
The Microsoft Windows Security Updates: April 2021
Click on the following link to download an Excel spreadsheet with the released security updates: Security-updates-windows-april-2021
Executive Summary
- Security updates are available for all supported versions of Windows (client and server).
- Microsoft released security updates for other company products including Azure, Microsoft Edge, Exchange Server, Microsoft Office, Visual Studio and Visual Studio Code, and Windows Media Player.
- If you manage Exchange Servers, check out this blog post on the April 2021 security updates.
- Several updates have known issues, including those for Windows 7 and 8.1, various Windows 10 versions, Windows Server versions, and Microsoft Exchange Server.
- Windows 10 version 1909 for Home customers runs out of support after the May 2021 Patch Day.
Operating System Distribution
- Windows 7Â Â (extended support only): 50 vulnerabilities: 14 critical and 36 important
- CVE-2021-27095Â -- Windows Media Video Decoder Remote Code Execution Vulnerability
- CVE-2021-28315 -- Windows Media Video Decoder Remote Code Execution Vulnerability
- CVE-2021-28329 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28330 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28331 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28332 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28333 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
CVE-2021-28334Â -- Remote Procedure Call Runtime Remote Code Execution Vulnerability - CVE-2021-28335 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28336 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28337 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28338 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28339 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28343 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- Windows 8.1: 5 5vulnerabilities: 14 critical and 41 important
- same as Windows 7
- Â Windows 10 version 1903 and 1909: 77 vulnerabilities: 14 critical and 62 important and 1 moderate
- same as Windows 7
- Windows 10 version 2004 and 20H2: 79 vulnerabilities, 14 critical and 64 important and 1 moderate
- same as Windows 7
Windows Server products
- Windows Server 2008 R2 (extended support only):Â 47 vulnerabilities: 14 critical and 33 important
- CVE-2021-27095Â -- Windows Media Video Decoder Remote Code Execution Vulnerability
- CVE-2021-28315 -- Windows Media Video Decoder Remote Code Execution Vulnerability
- CVE-2021-28329 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28330 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28331 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28332 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28333 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
CVE-2021-28334Â -- Remote Procedure Call Runtime Remote Code Execution Vulnerability - CVE-2021-28335 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28336 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28337 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28338 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28339 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- CVE-2021-28343 -- Remote Procedure Call Runtime Remote Code Execution Vulnerability
- Windows Server 2012 R2: 55Â vulnerabilities: 14 critical and 41 important
- same as Windows Sever 2008 R2
- Windows Server 2016: 63 vulnerabilities: 14 critical and 49 important.
- same as Windows Sever 2008 R2
- Windows Server 2019: 77 vulnerabilities: 14 critical and 62 important and 1 moderate
- same as Windows Sever 2008 R2
Windows Security Updates
Windows 7 SP1 and Windows Server 2008 R2
Updates and improvements:
- Time Zone change for Volgograd, Russia and The Republic of South Sudan.
- Removed support for the RemoteFX vGPU feature. Microsoft suggests to use secure vGPU alternatives. (Monthly Rollup only)
- Addressed an issue that prevents users from specifying up to 255 columns when using the Jet Text installable indexed sequential access method (IISAM) format. (Monthly Rollup only)
- Fixed a Windows Backup Event ID reporting issue. (Monthly Rollup only)
- Fixed security issues.
Windows 8.1 and Windows Server 2012 R2
Updates and improvements:
- Time Zone change for Volgograd, Russia and The Republic of South Sudan.
- Fixed security issues.
- Removed support for the RemoteFX vGPU feature. Microsoft suggests to use secure vGPU alternatives. (Monthly Rollup only)
- Addressed an issue that prevents users from specifying up to 255 columns when using the Jet Text installable indexed sequential access method (IISAM) format. (Monthly Rollup only)
Windows 10 version 1909
- Support Page: KB5001337
Updates and improvements:
- Fixed a "potential elevation of privilege vulnerability in the way Azure Active Directory web sign-in allows arbitrary browsing". See Policy CSP Authentication for more information.
- Fixed an issue in "which a principal in a trusted MIT realm fails to obtain a Kerberos service ticket from Active Directory domain controllers (DC)".
- Removed support for the RemoteFX vGPU feature. Microsoft suggests to use secure vGPU alternatives. (Monthly Rollup only)
- Security updates.
Windows 10 version 2004 and 20H2
- Support Page: KB5001330
Updates and improvements:
- same as Windows 10 version 1909
Other security updates
2021-04 Cumulative Update for Windows 10 Version 1507 (KB5001340)
2021-04 Cumulative Update for Windows 10 Version 1803 (KB5001339)
2021-04 Cumulative Update for Windows 10 Version 1809 (KB5001342)
2021-04 Security Only Quality Update for Windows Server 2008 (KB5001332)
2021-04 Security Monthly Quality Rollup for Windows Server 2008 (KB5001389)
2021-04 Security Only Quality Update for Windows Embedded 8 Standard and Windows Server 2012 (KB5001383)
2021-04 Security Monthly Quality Rollup for Windows Embedded 8 Standard and Windows Server 2012 (KB5001387)
2021-04 Cumulative Update for Windows Server 2016 and Windows 10 Version 1607 (KB5001347)
Known Issues
Windows 7 and Windows Server 2008 R2
- Updates may be reverted if the machine is not supported for ESU.
- Some operations may fail on Cluster Shared Volumes. Workaround available.
Windows 8.1 and Windows Server 2012 R2
- Some operations may fail on Cluster Shared Volumes. Workaround available.
Windows 10 version 1909
- System and user certificates may be lost when updating to a newer version of Windows. Workaround available, Microsoft is working on a solution.
Windows 10 version 2004 and 20H2
- System and user certificates may be lost when updating to a newer version of Windows. Workaround available, Microsoft is working on a solution.
- Issue with the Microsoft Japanese Input Method Editor and Kanji / Furigana characters.
- Some devices, created using custom offline media or ISO images, may have Edge Legacy removed but not replaced by the new Edge. Microsoft has a workaround for this.
Security advisories and updates
ADV 990001Â -- Latest Servicing Stack Updates
Non-security related updates
2021-04 Update for Windows 8.1, Windows Server 2012 R2, Windows Embedded 8 Standard, Windows Server 2012, Windows 7, Windows Server 2008 R2, and Windows Server 2008 (KB4601275)
Windows Malicious Software Removal Tool - v5.88 (KB890830)
Microsoft Office Updates
You find Office update information here.
How to download and install the April 2021 security updates
Security updates are installed automatically on most Windows devices thanks to the built-in automatic updating functionality. Administrators may run manual checks for updates to download and install updates early, or download updates directly from the Microsoft Update Catalog website or by using first-party or third-party update management tools and services.
Note: we recommend to create backups before the installation of updates, as updates may have issues.
Windows administrators may run the following steps to check for updates manually on Windows devices:
- Select Start, type Windows Update and load the Windows Update item that is displayed.
- 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
- KB5001335 -- 2021-04 Security Monthly Quality Rollup for Windows 7
- KB5001392 -- 2021-04 Security Only Quality Update for Windows 7
Windows 8.1 and Windows Server 2012 R2
- KB5001382 -- 2021-04 Security Monthly Quality Rollup for Windows 8.1
- KB5001393 -- 2021-04 Security Only Quality Update for Windows 8.1
Windows 10 (version 1909)
- KB5001337Â -- 2021-04 Cumulative Update for Windows 10 Version 1909
Windows 10 (version 2004)
- KB5001330Â -- 2021-04 Cumulative Update for Windows 10 Version 2004
Windows 10 (version 20H2)
- KB5001330 -- 2021-04 Cumulative Update for Windows 10 Version 20H2
Additional resources
Summary
Article Name
Microsoft Windows Security Updates April 2021 overview
Description
An overview of the security and non-security updates that Microsoft released on the April 2021 Patch Tuesday.
Author
Martin Brinkmann
Publisher
Ghacks Technology News
Logo
What mental age of reader are you targeting with the first sentence? 10?
Why not write an article on how to *avoid* upgrading from W10 to W11. Analogous to those like me who avoided upgrading from 7 to 10 for as long as possible.
If your paymaster Microsoft permits it, of course.
5. Rufus
6. Ventoy
PS. I hate reading these “SEO optimized” articles.
I used Rufus to create an installer for a 6th gen intel i5 that had MBR. It upgraded using Setup. No issues except for Win 11 always prompting me to replace my local account. Still using Win 10 Pro on all my other PCs to avoid the bullying.
bit pointless to upgrade for the sake of upgrading as you never know when you’ll get locked out because ms might suddenly not provide updates to unsupported systems.
ps…. time travelling?
written. Jan 15, 2023
Updated • Jan 13, 2023
This happens when you schedule a post in WordPress and update it before setting the publication date.
Anyone willing to downgrade to this awful OS must like inflicting themselves with harm.
I have become convinced now that anybody who has no qualms with using Windows 11/10 must fit into one of the following brackets:
1) Too young to remember a time before W10 and W11 (doesn’t know better)
2) Wants to play the latest games on their PC above anything else (or deeply needs some software which already dropped W7 support)
3) Doesn’t know too much about how computers work, worried that they’d be absolutely lost and in trouble without the “”latest security””
4) Microsoft apologist that tries to justify that the latest “features” and “changes” are actually a good thing, that improve Windows
5) Uses their computer to do a bare minimum of like 3 different things, browse web, check emails, etc, so really doesn’t fuss
Obviously that doesn’t cover everyone, there’s also the category that:
6) Actually liked W7 more than 10, and held out as long as possible before switching, begrudgingly uses 10 now
Have I missed any group off this list?
You have missed in this group just about any professional user that uses business software like CAD programs or ERP Programs which are 99% of all professional users from this list.
Linux doesn’t help anyone who is not a linux kid and apple is just a fancy facebook machine.
Microsoft has removed KB5029351 update
only from windows update though
KB5029351 is still available from the ms update catalog site
1. This update is labaled as PREVIEW if it causes issues to unintelligent people, then they shouldn’t have allowed Preview updates ot install.
2. I have installed it in a 11 years old computer, and no problems at all.
3. Making a big drama over a bluescreen for an updated labeled as preview is ridiculous.
This is probably another BS internet drama where people ran programs and scripts that modified the registry until they broke Windows, just for removing stuff that they weren’t even using just for the sake of it.
Maybe people should stop playing geeks and actually either use Windows 10 or Windows 11, but don’t try to modify things just for the sake of it.
Sometimes removing or stopping things (like defender is a perfect example) only need intelligence, not scripts or 3rd party programs that might mess with windows.
Windows 11 was a pointless release, it was just created because some of the Windows team wanted to boost sales with some sort of new and improved Windows 10. Instead, Microsoft cannot support one version well let alone two.
Windows 11 is the worst ugly shame by Microsoft ever. They should release with every new W11 version a complete free version of Starallback inside just to make this sh** OS functionally again.
motherboard maker MSI has recently released a statement regarding the “unsupported processor” blue screen error for their boards using Intel 600/700 series chipsets & to avoid the KB5029351 Win11 update:
https://www.msi.com/news/detail/MSI-On–UNSUPPORTED-PROCESSOR–Error-Message-of-Windows-11-Update-KB5029351-Preview-142215
check out the following recent articles:
Neowin – Microsoft puts little blame on its Windows update after UNSUPPORTED PROCESSOR BSOD bug:
https://www.neowin.net/news/microsoft-puts-little-blame-on-its-windows-update-after-unsupported-processor-bsod-bug/
BleepingComputer – Microsoft blames ‘unsupported processor’ blue screens on OEM vendors:
https://www.bleepingcomputer.com/news/microsoft/microsoft-blames-unsupported-processor-blue-screens-on-oem-vendors/
While there may be changes or updates to the Windows 10 Store for Business and Education in the future, it is premature to conclude that it will be discontinued based solely on rumors.
My advice, I left win 15 years ago. Now I’m a happy linux user (linuxmint) but there is Centos, Fedora, Ubuntu depending on your needs.
motherboard maker MSI has recently released new BIOS/firmware updates for their Intel 600 & 700 series motherboards to fix the “UNSUPPORTED_PROCESSOR” problem (Sept. 6):
https://www.msi.com/news/detail/Updated-BIOS-fixes-Error-Message–UNSUPPORTED-PROCESSOR–caused-BSOD-on-MSI-s-Intel-700-and-600-Series-Motherboards-142277
I try to disable the Diagnostics Tracking Service (Connected Devices Platform User Services) but it wont let me disable it, any help will be greatly appreciated.
Tank you for your help