October 13, 2020—KB4580330 (OS Build 17134.1792) - EXPIRED

NEW 8/5/21
EXPIRATION NOTICE****IMPORTANTAs of 8/5/2021, this KB is no longer available from Windows Update, the Microsoft Update Catalog, or other release channels. We recommend that you update your devices to the latest security quality update.

NEW
IMPORTANTRelease notes are changing! To learn about the new URL, metadata updates, and more, see What’s next for Windows release notes.

IMPORTANT We have heard your feedback and understand your need to focus on business continuity in the midst of the global pandemic. As a result, we have decided to delay the scheduled end-of-service date for the Enterprise, Education, and IoT Enterprise editions of Windows 10, version 1803. The final security update for these editions of Windows 10, version 1803 will be released on May 11, 2021 instead of November 10, 2020.

IMPORTANT Windows 10, version 1803 has reached the end of mainstream support and is 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).

IMPORTANTStarting in July 2020, all Windows Updates will disable the RemoteFX vGPU feature because of a security vulnerability. For more information about the vulnerability, seeCVE-2020-1036 and KB4570006. After you install this update, attempts to start virtual machines (VM) that have RemoteFX vGPU enabled will fail, and messages such as the following will appear:If you re-enable RemoteFX vGPU, a message similar to the following will appear:

• “The virtual machine cannot be started because all the RemoteFX-capable GPUs are disabled in Hyper-V Manager.”
• “The virtual machine cannot be started because the server has insufficient GPU resources.”
• "We no longer support the RemoteFX 3D video adapter. If you are still using this adapter, you may become vulnerable to security risk. Learn more (https://go.microsoft.com/fwlink/?linkid=2131976)”

Windows 10, version 1803 (the April 2018 Update) Home and Pro editions have reached end of service. For Windows 10 devices that are at, or within several months of reaching end of service, Windows Update will automatically initiate a feature update (with users having the ability to choose a convenient time). This keeps those devices supported and receiving the monthly updates that are critical to device security and ecosystem health.

Highlights

• Adds a notification to Internet Explorer 11 that informs users about the end of support for Adobe Flash in December 2020. For more information, see KB4581051.
• Updates 2021 time zone information for Fiji.
• Updates to improve security when using Microsoft Office products.
• Updates for verifying usernames and passwords.
• Updates to improve security when Windows performs basic operations.
• Updates for storing and managing files.

Improvements and fixes

This security update includes quality improvements. Key changes include:

• Adds a notification to Internet Explorer 11 that informs users about the end of support for Adobe Flash in December 2020. For more information, see KB4581051.
• Addresses an issue with Microsoft Edge IE Mode that occurs when you enable Configure enhanced hang detection for Internet Explorer mode in Microsoft Edge.
• Allows administrators to disable JScript in specific security zones.
• Addresses an issue with a possible elevation of privilege in win32k.
• Updates 2021 time zone information for Fiji.
• Addresses an issue with the Group Policy service that might recursively delete critical files in alphabetic order from %systemroot%\system32. This issue occurs when a policy has been configured to delete cached profiles. These file deletions might cause stop error “0x5A (CRITICAL_SERVICE_FAILED)” boot failures.
• Addresses an issue with creating null ports using the user interface.
• Security updates to Windows App Platform and Frameworks, Microsoft Graphics Component, Windows Media, Windows Fundamentals, Windows Authentication, Windows Virtualization, Windows Kernel, and Windows Storage and Filesystems.
  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

• 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.

How to get this update