February 9, 2021—KB4601349 (Security-only update)

IMPORTANT Windows 8.1 and Windows Server 2012 R2 have reached the end of mainstream support and are now in extended support. Starting in July 2020, there will no longer be optional, non-security releases (known as “C” releases) for this operating system. Operating systems in extended support have only cumulative monthly security updates (known as the “B” or Update Tuesday release).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 8.1 and Windows Server 2012 R2 update history home page.

Improvements and fixes

This security update includes quality improvements. Key changes include:

• Adds historical daylight saving time (DST) updates and corrections for the Palestinian Authority.
• Addresses an issue with German translations of Central European Time.
• Updates the Netlogon Elevation of Privilege Vulnerability (CVE-2020-1472) to enable Enforcement mode. For more details, see CVE-2020-1472 and How to manage the changes in Netlogon secure channel connections associated with CVE-2020-1472.
• Security updates to Windows App Platform and Frameworks, Windows Hybrid Cloud Networking, and Windows Core Networking.
  For more information about the resolved security vulnerabilities, please refer to the new Security Update Guide website.

Known issues in this update

• 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.

How to get this update

Before installing this update

We strongly recommend that you install the latest servicing stack update (SSU) for your operating system before you install the latest Rollup. SSUs improve the reliability of the update process to mitigate potential issues while installing the Rollup and applying Microsoft security fixes. For general information about SSUs, see Servicing stack updates and Servicing Stack Updates (SSU): Frequently Asked Questions.If you use Windows Update, the latest SSU (KB4566425) will be offered to you automatically. To get the standalone package for the latest SSU, search for it in the Microsoft Update Catalog. 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 (KB4586768).

Install this update

File information

For a list of the files that are provided in this update, download the file information for update 4601349.