Microsoft has published the April 2021 security updates.

April 2021 Security Updates

Updates this Month

This release consists of security updates for the following products, features and roles.

• Azure AD Web Sign-in
• Azure DevOps
• Azure Sphere
• Microsoft Edge (Chromium-based)
• Microsoft Exchange Server
• Microsoft Graphics Component
• Microsoft Internet Messaging API
• Microsoft NTFS
• Microsoft Office Excel
• Microsoft Office Outlook
• Microsoft Office SharePoint
• Microsoft Office Word
• Microsoft Windows Codecs Library
• Microsoft Windows Speech
• Open Source Software
• Role: DNS Server
• Role: Hyper-V
• Visual Studio
• Visual Studio Code
• Visual Studio Code - GitHub Pull Requests and Issues Extension
• Visual Studio Code - Kubernetes Tools
• Visual Studio Code - Maven for Java Extension
• Windows Application Compatibility Cache
• Windows AppX Deployment Extensions
• Windows Console Driver
• Windows Diagnostic Hub
• Windows Early Launch Antimalware Driver
• Windows ELAM
• Windows Event Tracing
• Windows Installer
• Windows Kernel
• Windows Media Player
• Windows Network File System
• Windows Overlay Filter
• Windows Portmapping
• Windows Registry
• Windows Remote Procedure Call Runtime
• Windows Resource Manager
• Windows Secure Kernel Mode
• Windows Services and Controller App
• Windows SMB Server
• Windows TCP/IP
• Windows Win32K
• Windows WLAN Auto Config Service

Please note the following information regarding the security updates:

Security Update Guide Blog Posts

Date	Blog Post
February 9, 2021	Continuing to Listen: Good News about the Security Update Guide API
January 13, 2021	Security Update Guide Supports CVEs Assigned by Industry Partners
December 8, 2020	Security Update Guide: Let’s keep the conversation going
November 9, 2020	Vulnerability Descriptions in the New Version of the Security Update Guide

Relevant Information

• Windows 10 updates are cumulative. The monthly security release includes all security fixes for vulnerabilities that affect Windows 10, in addition to non-security updates. The updates are available via the Microsoft Update Catalog. For information on lifecycle and support dates for Windows 10 operating systems, please see Windows Lifecycle Facts Sheet.
• Microsoft is improving Windows Release Notes. For more information, please see What's next for Windows release notes.
• A list of the latest servicing stack updates for each operating system can be found in ADV990001. This list will be updated whenever a new servicing stack update is released. It is important to install the latest servicing stack update.
• In addition to security changes for the vulnerabilities, updates include defense-in-depth updates to help improve security-related features.
• Customers running Windows 7, Windows Server 2008 R2, or Windows Server 2008 need to purchase the Extended Security Update to continue receiving security updates. See 4522133 for more information.

FAQs, Mitigations, and Workarounds

The following CVEs have FAQs, Mitigations, or Workarounds. You can see these in more detail from the Vulnerabilities tab by selecting FAQs, Mitigations and Workarounds columns in the Edit Columns panel.

• CVE-2021-21194
• CVE-2021-21195
• CVE-2021-21196
• CVE-2021-21197
• CVE-2021-21198
• CVE-2021-21199
• CVE-2021-26416
• CVE-2021-26417
• CVE-2021-27067
• CVE-2021-27079
• CVE-2021-27093
• CVE-2021-27095
• CVE-2021-28309
• CVE-2021-28315
• CVE-2021-28317
• CVE-2021-28318
• CVE-2021-28323
• CVE-2021-28324
• CVE-2021-28325
• CVE-2021-28328
• CVE-2021-28435
• CVE-2021-28437
• CVE-2021-28441
• CVE-2021-28442
• CVE-2021-28444
• CVE-2021-28446
• CVE-2021-28449
• CVE-2021-28451
• CVE-2021-28452
• CVE-2021-28453
• CVE-2021-28454
• CVE-2021-28456
• CVE-2021-28460
• CVE-2021-28464
• CVE-2021-28466
• CVE-2021-28468
• CVE-2021-28480
• CVE-2021-28481
• CVE-2021-28482
• CVE-2021-28483

Known Issues

You can see these in more detail from the Deployments tab by selecting Known Issues column in the Edit Columns panel.

For more information about Windows Known Issues, please see Windows message center (links to currently-supported versions of Windows are in the left pane).

KB Article	Applies To
4504715	SharePoint Server 2019 Language Pack
4504716	SharePoint Server 2019
5001330	Windows 10, Version 2004, Windows Server, Version 2004, Windows 10, Version 20H2, Windows Server, Version 20H2
5001332	Windows Server 2008 (Security-only update)
5001335	Windows 7, Windows Server 2008 R2 (Monthly Rollup)
5001337	Windows 10, Version 1909, Windows Server, Version 1909
5001342	Windows 10, Version 1809, Windows Server 2019
5001347	Windows 10, Version 1607, Windows Server 2016
5001382	Windows 8.1, Windows RT 8.1, Windows Server 2012 R2 (Monthly Rollup)
5001383	Windows Server 2012 (Security-only update)
5001387	Windows Server 2012 (Monthly Rollup)
5001389	Windows Server 2008 (Monthly Rollup)
5001392	Windows 7, Windows Server 2008 R2 (Security-only update)
5001393	Windows 8.1, Windows RT 8.1, Windows Server 2012 R2 (Security-only update)
5001779	Microosft Exchange Server 2019, 2016, 2013

Security Update Guide - Microsoft Security Response Center