October 13, 2020—KB4579311 (OS Build 19041.572)

Applies to: Windows 10, version 2004, all editionsWindows Server version 2004

Highlights


  • Updates to improve security when using Microsoft Office products.
  • Updates for verifying usernames and passwords.
  • Updates to improve security when Windows performs basic operations.

Improvements and fixes


    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.

    Known issues in this update


    Symptom Workaround
    Users of the Microsoft Input Method Editor (IME) for Japanese or Chinese languages might experience issues when attempting various tasks. You might have issues with input, receive unexpected results, or might not be able to enter text. All IME issues listed in KB4564002 were resolved in KB4586853.
    When installing a third-party driver, you might receive the error, “Windows can’t verify the publisher of this driver software”. You might also see the error, “No signature was present in the subject” when attempting to view the signature properties using Windows Explorer.

    This issue occurs when one or more of the following is present in a driver package:

    • An improperly formatted catalog file is identified during validation by Windows. Starting with this release, Windows will require the validity of DER encoded PKCS#7 content in catalog files. Catalogs files must be signed per section 11.6 of describing DER-encoding for SET OF members in X.690.
    • A driver catalog file extension is not one of supported extensions.

    If this happens you should contact the driver vendor or device manufacturer (OEM) and ask them for an updated driver to correct the issue.

    System and user certificates might be lost when updating a device from Windows 10, version 1809 or later to a later version of Windows 10. Devices will only be impacted if they have already installed any Latest cumulative update (LCU) released September 16, 2020 or later and then proceed to update to a later version of Windows 10 from media or an installation source which does not have an LCU released October 13, 2020 or later integrated. This primarily happens when managed devices are updated using outdated bundles or media through an update management tool such as Windows Server Update Services (WSUS) or Microsoft Endpoint Configuration Manager. This might also happen when using outdated physical media or ISO images that do not have the latest updates integrated.

    Note Devices using Windows Update for Business or that connect directly to Windows Update are not impacted. Any device connecting to Windows Update should always receive the latest versions of the feature update, including the latest LCU, without any extra steps.

    If you have already encountered this issue on your device, you can mitigate it within the uninstall window by going back to your previous version of Windows using the instructions here. The uninstall window might be 10 or 30 days depending on the configuration of your environment and the version you’re updating to. You will then need to update to the later version of Windows 10 after the issue is resolved in your environment. Note Within the uninstall window, you can increase the number of days you have to go back to your previous version of Windows 10 by using the DISM command /Set-OSUninstallWindow. You must make this change before the default uninstall window has lapsed. For more information, see DISM operating system uninstall command-line options.

    We are working on a resolution and will provide updated bundles and refreshed media in the coming weeks.

    When using the Microsoft Japanese Input Method Editor (IME) to enter Kanji characters in an app that automatically allows the input of Furigana characters, you might not get the correct Furigana characters. You might need to enter the Furigana characters manually.

    Note The affected apps are using the ImmGetCompositionString() function.

    We are working on a resolution and will provide an update in an upcoming release.

     

    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 (KB4577266) will be offered to you automatically. To get the standalone package for the latest SSU, search for it in the Microsoft Update Catalog.

    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 4579311

    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.