March 9, 2021—KB5000851 (Security-only update)

Important:Verify that****you have installed the required updates listed in theHow to get this update section before installing this update.

**Important:**For information about the various types of Windows updates, such as critical, security, driver, service packs, and so on, please see the following article. To view other notes and messages, see the Windows 7 SP1 and Windows Server 2008 R2 SP1 update history home page.

Improvements and fixes

This security update includes quality improvements. Key changes include:

• Addresses an issue in which a non-native device that is in the same realm does not receive a Kerberos Service ticket from Active Directory DCs. This issue occurs even though Windows Updates are installed that contain CVE-2020-17049 protections released between November 10 and December 8, 2020 and configured PerfromTicketSignature to1or larger. Ticket acquisition fails withKRB_GENERIC_ERRORif callers submit a PAC-less Ticket Granting Ticket (TGT) as an evidence ticket without theUSER_NO_AUTH_DATA_REQUIRED flag being set for the user in User Account Controls.
• Security updates to Windows Fundamentals, Windows Shell, Windows UAC, Windows Hybrid Cloud Networking, and Windows Media.
  For more information about the resolved security vulnerabilities, please refer to the new Security Update Guide website.

Known issues in this update

• If you are installing this update on a device that is running an edition that is not supported for ESU. For a complete list of which editions are supported, see KB4497181.

• If you do not have an ESU MAK add-on key installed and activated.
  If you have purchased an ESU key and have encountered this issue, please verify you have applied all prerequisites and that your key is activated. For information on activation, please see this blog post. For information on the prerequisites, see the “How to get this update” section of this article.
  Certain operations, such as rename, that you perform on files or folders that are on a Cluster Shared Volume (CSV) may fail with the error, “STATUS_BAD_IMPERSONATION_LEVEL (0xC00000A5)”. This occurs when you perform the operation on a CSV owner node from a process that doesn’t have administrator privilege.| Do one of the following:

• Perform the operation from a process that has administrator privilege.

• Perform the operation from a node that doesn’t have CSV ownership.
  Microsoft is working on a resolution and will provide an update in an upcoming release.
  After installing updates released March 9, 2021, you might get unexpected results when printing from some apps. Issues might include:

• Elements of the document might print as solid black/color boxes or might be missing, including barcodes, QR codes, and graphics elements, such as logos.

• Table lines might be missing. Other alignment or formatting issues might also be present.

• Printing from some apps or to some printers might result in a blank page or label.
  | This issue is resolved in KB5001639.

How to get this update

Before installing this update

IMPORTANT Customers who have purchased the Extended Security Update (ESU) for on-premises versions of these operating systems must follow the procedures in KB4522133 to continue receiving security updates after extended support ends. Extended support ends as follows:

• For Windows 7 Service Pack 1 and Windows Server 2008 R2 Service Pack 1, extended support ends on January 14, 2020.
• For Windows Embedded Standard 7, extended support ends on October 13, 2020.
  For more information about ESU and which editions are supported, see KB4497181.Note For Windows Embedded Standard 7, Windows Management Instrumentation (WMI) must be enabled to get updates from Windows Update or Windows Server Update Services.Prerequisite:You must install the updates listed below andrestart your device before installing the latest Rollup. Installing these updates improves the reliability of the update process and mitigates potential issues while installing the Rollup and applying Microsoft security fixes.

1. The March 12, 2019 servicing stack update (SSU) (KB4490628). To get the standalone package for this SSU, search for it in the Microsoft Update Catalog. This update is required to install updates that are only SHA-2 signed.
2. The latest SHA-2 update (KB4474419) released September 10, 2019. If you are using Windows Update, the latest SHA-2 update will be offered to you automatically. This update is required to install updates that are only SHA-2 signed. For more information on SHA-2 updates, see 2019 SHA-2 Code Signing Support requirement for Windows and WSUS.
3. For Windows Thin PC, you must have the August 11, 2020 SSU (KB4570673) or a later SSU installed to make sure you continue to get the extended security updates starting with the October 13, 2020 updates.
4. To get this security update, you must reinstall the “Extended Security Updates (ESU) Licensing Preparation Package” (KB4538483) or the “Update for the Extended Security Updates (ESU) Licensing Preparation Package” (KB4575903) even if you previously installed the ESU key. The ESU licensing preparation package will be offered to you from WSUS. To get the standalone package for ESU licensing preparation package, search for it in the Microsoft Update Catalog.
   After installing the items above, Microsoft strongly recommends that you install the latest SSU (KB4592510). If you are using Windows Update, the latest SSU will be offered to you automatically if you are an ESU customer. To get the standalone package for the latest SSU, search for it in the Microsoft Update Catalog. For general information about SSUs, see Servicing stack updates and Servicing Stack Updates (SSU): Frequently Asked Questions.REMINDER If you are using Security-only updates, you will also need to install all previous Security-only updates and the latest cumulative update for Internet Explorer (KB5000800).

Install this update

File information

For a list of the files that are provided in this update, download the file information for cumulative update 5000851.