July 6, 2021—KB5004946 (OS Build 18363.1646) Out-of-band

EXPIRATION NOTICEAs of 9/12/2023, KB5004946 is only available from Windows Update. This update is no longer available from the Microsoft Update Catalog, or other release channels. We recommend that you update your devices to the latest security quality update.

**6/15/21
IMPORTANT **This release includes the Flash Removal Package. Taking this update will remove Adobe Flash from the machine. For more information, see the Update on Adobe Flash Player End of Support.

5/11/21 **REMINDER **Windows 10, version 1909 reached end of service on May 11, 2021 for devices running the Home, Pro, Pro for Workstation, Nano Container, and Server SAC editions. After May 11, 2021, these devices will no longer receive monthly security and quality updates that contain protection from the latest security threats. To continue receiving security and quality updates, Microsoft recommends updating to the latest version of Windows 10We will continue to service the following editions: Enterprise, Education, and IoT Enterprise.

11/19/20
For information about Windows update terminology, see the article about the types of Windows updates and the monthly quality update types. To view other notes and messages, see the Windows 10, version 1909 update history home page.NoteFollow @WindowsUpdate to find out when new content is published to the release information dashboard.

Highlights

• Updates a remote code execution exploit in the Windows Print Spooler service, known as “PrintNightmare”, as documented in CVE-2021-34527.

Improvements and fixes

This security update includes quality improvements. Key changes include:

• Addresses a remote code execution exploit in the Windows Print Spooler service, known as “PrintNightmare”, as documented in CVE-2021-34527. After installing this and later Windows updates, users who are not administrators can only install signed print drivers to a print server. By default, administrators can install signed and unsigned printer drivers to a print server. The installed root certificates in the system’s Trusted Root Certification Authorities trusts signed drivers. Microsoft recommends that you immediately install this update on all supported Windows client and server operating system, starting with devices that currently host the print server role. You also have the option to configure the RestrictDriverInstallationToAdministrators registry setting to prevent non-administrators from installing signed printer drivers on a print server. For more information, see KB5005010.
  If you installed earlier updates, only the new fixes contained in this package will be downloaded and installed on your device.

Windows Update ImprovementsMicrosoft has released an update directly to the Windows Update client to improve reliability. Any device running Windows 10 configured to receive updates automatically from Windows Update, including Enterprise and Pro editions, will be offered the latest Windows 10 feature update based on device compatibility and Windows Update for Business deferral policy. This doesn’t apply to long-term servicing editions.

Known issues in this update

Microsoft is not currently aware of any issues with this update.

How to get this update