CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AI Score
Confidence
High
EPSS
Percentile
98.4%
**9/26/23
IMPORTANT **After September 26, 2023, there will no longer be optional, non-security preview releases for Windows 11, version 21H2. Only cumulative monthly security updates will continue for the supported versions of Windows 11, version 21H2.
UPDATED 10/10/2023 **REMINDER **Some editions of Windows 11, version 21H2 are at end of service today, October 10, 2023. These are Home, Pro, Pro Education, and Pro for Workstation. After today, devices that run these editions will not receive monthly security and quality updates. These updates contain protections from the latest security threats.We will continue to support the remaining editions of Windows 11, version 21H2.
For information about Windows update terminology, see the article about the types of Windows updates and the monthly quality update types. For an overview of Windows 11, version 21H2, see its update history page.NoteFollow @WindowsUpdate to find out when new content is published to the Windows release health dashboard.
**Tip:**Looking for this month’s video? It’s now in the Windows 11, version 22H2 article.
This security update includes improvements that were a part of update KB5030301 (released September 26, 2023). When you install this KB:
* 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 keys 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\ParametersThese 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 | 400 | 0–65535 | Sets the allowed number of resets (RST_STREAMS) per minute for a connection. When you reach this limit, a GOAWAY message is sent to client for the connection. |
Http2MaxClientResetsGoaway | 1 | 0-1 | Disables or enables the GOAWAY message to send when you reach the limit. If you set this to 0, the connection ends as soon as you reach the limit. |
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 Security Update Guide website and the October 2023 Security Updates. |
This update makes quality improvements to the servicing stack, which is the component that installs Windows updates. Servicing stack updates (SSU) ensure that you have a robust and reliable servicing stack so that your devices can receive and install Microsoft updates.
Applies to | Symptom | Workaround |
---|---|---|
IT admins | Using the FixedDrivesEncryptionType or SystemDrivesEncryptionType policy settings in the BitLocker configuration service provider (CSP) node in mobile device management (MDM) apps might incorrectly show a 65000 error in the “Require Device Encryption” setting for some devices in your environment. Affected environments are those with the “Enforce drive encryption type on operating system drives” or “Enforce drive encryption on fixed drives” policies set to enabled and selecting either “full encryption” or “used space only”. Microsoft Intune is affected by this issue but third-party MDMs might also pe affected. Important This issue is a reporting issue only and does not affect drive encryption or the reporting of other issues on the device, including other BitLocker issues. | This issue is addressed in KB5034121. |
Before installing this updateMicrosoft combines the latest servicing stack update (SSU) for your operating system with the latest cumulative update (LCU). For general information about SSUs, see Servicing stack updates and Servicing Stack Updates (SSU): Frequently Asked Questions.Install this update****Release Channel | Available | Next Step |
---|---|---|
Windows Update and Microsoft Update | Yes | None. This update will be downloaded and installed automatically from Windows Update. |
Windows Update for Business | Yes | None. This update will be downloaded and installed automatically from Windows Update in accordance with configured policies. |
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 11Classification: Security Updates |
If you want to remove the LCUTo remove the LCU after installing the combined SSU and LCU package, use the DISM/Remove-Package command line option with the LCU package name as the argument. You can find the package name by using this command:DISM /online /get-packages.Running Windows Update Standalone Installer (wusa.exe) with the**/uninstall **switch on the combined package will not work because the combined package contains the SSU. You cannot remove the SSU from the system after installation.
File informationFor a list of the files that are provided in this update, download the file information for cumulative update 5031358. For a list of the files that are provided in the servicing stack update, download the file information for the SSU - version 22000.2531.