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May 12, 2020—KB4556799 (OS Builds 18362.836 and 18363.836)

Release Date:

12/05/2020

Version:

1903-OS Build 18362.836 and 1909-OS Build 18363.836

IMPORTANT We have been evaluating the public health situation, and we understand this is impacting our customers. In response to these challenges, we are prioritizing our focus on security updates. Starting in May 2020, we are pausing all optional non-security releases (C and D updates) for all the supported versions of Windows client and server products (Windows 10, version 1909 down to Windows Server 2008 SP2).

There is no change to the monthly security updates (B release – Update Tuesday); these will continue as planned to ensure business continuity and to keep our customers protected and productive.

What's new for Windows 10, version 1909 and Windows 10, version 1903 release notes

Windows 10, versions 1903 and 1909 share a common core operating system and an identical set of system files. As a result, the new features in Windows 10, version 1909 were included in the recent monthly quality update for Windows 10, version 1903 (released October 8, 2019), but are currently in a dormant state. These new features will remain dormant until they are turned on using an enablement package, which is a small, quick-to-install “master switch” that simply activates the Windows 10, version 1909 features.

To reflect this change, the release notes for Windows 10, version 1903 and Windows 10, version 1909 will share an update history page. Each release page will contain a list of addressed issues for both 1903 and 1909 versions. Note that the 1909 version will always contain the fixes for 1903; however, 1903 will not contain the fixes for 1909. This page will provide you with the build numbers for both 1909 and 1903 versions so that it will be easier for support to assist you if you encounter issues.

For more details about the enablement package and how to get the feature update, see the Windows 10, version 1909 delivery options blog.

For more information about the various types of Windows updates, such as critical, security, driver, service packs, and so on, please see the following article.

Note Follow @WindowsUpdate to find out when new content is published to the release information dashboard.

Highlights

  • Updates to improve security when using Internet Explorer and Microsoft Edge.

  • Updates to improve security when using input devices such as a mouse, keyboard, or stylus.

  • Updates for verifying usernames and passwords.

  • Updates to improve security when using Microsoft Xbox.

  • Updates to improve security when Windows performs basic operations.

  • Updates for storing and managing files.

  • Updates to improve security when using Microsoft Office products.

Improvements and fixes

This security update includes quality improvements. Key changes include:

  • This build includes all the improvements from Windows 10, version 1903.

  • No additional issues were documented for this release.

Note This release also contains updates for Microsoft HoloLens (OS Build 18362.1061) released May 12, 2020. Microsoft will release an update directly to the Windows Update Client to improve Windows Update reliability on Microsoft HoloLens that have not updated to this most recent OS Build.

This security update includes quality improvements. Key changes include:

  • Updates the 2020 start date for daylight saving time (DST) in the Kingdom of Morocco.

  • Addresses a security issue described in CVE-2018-0886 by adding support for the “Encryption Oracle Remediation” policy setting and changing the default value from Vulnerable to Mitigated. For more information about how this might affect your environment if you are using Remote Desktop, see KB4093492.

  • Security updates to Internet Explorer, the Microsoft Scripting Engine, Windows App Platform and Frameworks, Microsoft Graphics Component, Windows Input and Composition, Windows Media, Windows Shell, Microsoft Xbox, Microsoft Edge, Windows Fundamentals, Windows Cryptography, Windows Authentication, Windows Kernel, Windows Linux, Windows Update Stack, Windows Network Security and Containers, Windows Active Directory, Windows Storage and Filesystems, and the Microsoft JET Database Engine.

If you installed earlier updates, only the new fixes contained in this package will be downloaded and installed on your device.

For more information about the resolved security vulnerabilities, please refer to the Security Update Guide.

Windows Update Improvements

Microsoft has released an update directly to the Windows Update client to improve reliability. Any device running Windows 10 configured to receive updates automatically from Windows Update, including Enterprise and Pro editions, will be offered the latest Windows 10 feature update based on device compatibility and Windows Update for Business deferral policy. This doesn't apply to long-term servicing editions.

 

Known issues in this update

Symptom

Workaround

We have seen social media and news reports related to various issues with KB4556799.

We are actively engaged with customers who are reporting issues. To date, we have not seen widespread issues reflected in telemetry, support data, or customer feedback channels. We continuously investigate all customer feedback and are closely monitoring this situation.

Note If you experience any issues, we'd like to know. Please provide feedback using the keyboard shortcut Windows + F or go to the Start menu and select Feedback Hub so that we can investigate.

After installing this update on a Windows 10 device with a wireless wide area network (WWAN) LTE modem, reaching the internet might not be possible. However, the Network Connectivity Status Indicator (NCSI) in the notification area might still indicate that you are connected to the internet.

This issue is resolved in KB4559004.

The Local Security Authority Subsystem Service (LSASS) file (lsass.exe) might fail on some devices with the error message, “A critical system process, C:\WINDOWS\system32\lsass.exe, failed with status code c0000008. The machine must now be restarted."

This issue is resolved in KB4565483.

 

How to get this update

Before installing this update

Microsoft strongly recommends you install the latest servicing stack update (SSU) for your operating system before installing the latest cumulative update (LCU). SSUs improve the reliability of the update process to mitigate potential issues while installing the LCU and applying Microsoft security fixes. For general information about SSUs, see Servicing stack updates and Servicing Stack Updates (SSU): Frequently Asked Questions.

If you are using Windows Update, the latest SSU (KB4552152) will be offered to you automatically. To get the standalone package for the latest SSU, search for it in the Microsoft Update Catalog.

Install this update

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:

Product: Windows 10, version 1903 and later

Classification: Security Updates

 

File information

For a list of the files that are provided in this update, download the file information for cumulative update 4556799

Note Some files erroneously have “Not applicable” in the “File version” column of the CSV file. This might lead to false positives or false negatives when using some third-party scan detection tools to validate the build.

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