October 10, 2023—KB5031377 (OS Build 10240.20232)

Highlights

• This update supports daylight saving time (DST) changes in Greenland. 

• This update addresses security issues for your Windows operating system. 

Improvements 

This security update includes quality improvements. When you install this KB: 

• This update changes the spelling of Ukraine's capital from Kiev to Kyiv.

• This update addresses an issue that affects external binding. It fails. This occurs after you install Windows updates dated May 2023 or later. Because of this, there are issues that affect LDAP queries and authentication.

• To protect against CVE-2023-44487, you should install the latest Windows update. Based on your use case, you can also set the limit of the RST_STREAMS per minute using the new registry key in this update. 

  You can create the DWORD registry values in the table below under the following registry key: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\HTTP\Parameters

  These keys are not present by default when you install this KB. You can create them as required to set new values for your environment.

  Registry key	Default value	Valid value range	Registry key function
  Http2MaxClientResetsPerMinute	500	0–65535	Sets the allowed number of resets (RST_STREAMS) per minute for a connection. When you reach this limit, the connection ends.

If you installed earlier updates, only the new updates contained in this package will be downloaded and installed on your device.

For more information about security vulnerabilities, please refer to the new Security Update Guide website and the October 2023 Security Updates.

Known issues in this update

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

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 updates.  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 (KB5031466) will be offered to you automatically. To get the standalone package for the latest SSU, search for it in the Microsoft Update Catalog.

Install this update

File information

For a list of the files that are provided in this update, download the file information for cumulative update 5031377.