October 13, 2020—KB4580328 (OS Build 16299.2166)

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

**NEW
IMPORTANT **We previously delayed the scheduled end of service date from April 2020 to October 2020 for the Enterprise, Education, and IoT Enterprise editions of Windows 10, version 1709. This release, dated October 13, 2020, is the final security update for these editions of Windows 10, version 1709. To continue receiving security and quality updates, Microsoft recommends updating to the latest version of Windows 10.

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.

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 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.
• Updates 2021 time zone information for Fiji.

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.
• 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 Shell, Windows Cloud Infrastructure, 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