KB5034763: Cumulative update for Windows 10, versions 21H2 and 22H2, February 2024. Closes exploited kernel, SmartScreen and shortcut-file flaws

Closes three exploited security flaws, including one in the Windows kernel, and addresses several Windows 10 issues. It is no longer available; Microsoft recommends updating to the latest Windows version.

Does it affect you? Applies to: This update applies to Windows 10, version 22H2, and Windows 10, version 21H2 Enterprise and Education editions, Windows 10 IoT Enterprise, and Windows 10 Enterprise multi-session.

Review notes Additional details from the official release notes (1) Read note

What changes Windows 10, version 22H2 includes all the improvements listed for supported Windows 10, version 21H2 editions, including these three fixes.

The official sources are linked at the end of the page.

What changes

Fixes 3 changes

explorer.exe

Addresses an issue that might make explorer.exe stop responding when you restart or shut down a PC with a controller accessory attached.¹

Certificate Authority snap-in

For: Windows 10, version 21H2 supported editions

Addresses an issue that prevented selecting the Delta CRL option to publish Delta CRLs through the GUI.²

Windows Update

For: Some eligible devices upgrading to Windows 11

Addresses an issue that might send some eligible devices error 0xd0000034 when they try to upgrade to Windows 11 through Windows Update.³

Improvements 3 changes

Windows 10, version 22H2

For: Windows 10, version 22H2 devices

Version 22H2 includes the improvements listed for supported Windows 10, version 21H2 editions.⁴

Device metadata

For: Windows 10, version 21H2 supported editions

Downloads of device metadata from WMIS over HTTPS are more secure.⁵
Applies to downloads from Windows Metadata and Internet Services (WMIS) over HTTPS.

Servicing stack

For: Windows 10 devices

The component that installs Windows updates receives quality improvements.⁶
Includes a servicing stack update for builds 19044.3989 and 19045.3989.

Known issues

Resolved Affects: Organizations and IT administrators Resolved by KB5040525

After you install KB5034203 (dated 01/23/2024) or later updates, some Windows devices that use the [DHCP Option 235](https://learn.microsoft.com/tr…

The issue that can make some devices using DHCP Option 235 download updates and apps from the public internet instead of Microsoft Connected Cache nodes is resolved by KB5040525. Home users are not likely to be affected.⁷

Resolution Fixed in KB5040525

Install KB5040525 (or a later cumulative update) on affected devices. No manual workaround is required after updating.
Open Affects: Everyone

Windows devices using more than one (1) monitor might experience issues with desktop icons moving unexpectedly between monitors or other icon alignment issues when attempting to use Copilot in Window…

On devices with more than one monitor, using Copilot in Windows (in preview) might move desktop icons between monitors or cause other icon alignment issues.⁸

How to apply the workaround Workaround

A new Copilot experience is gradually rolling out to devices with KB5039299 or later and is expected to address the issue.⁸
Open Affects: Everyone

Copilot in Windows (in preview) is not currently supported when your taskbar is located vertically on the right or left of your screen.

Copilot in Windows (in preview) is not currently supported when the taskbar is positioned vertically on the left or right of the screen.⁸

How to apply the workaround Workaround

A new Copilot experience is gradually rolling out to devices with KB5039299 or later and is expected to address the issue.⁸

Technical details

Data sheet · Security · Downloads · Components Click to collapse or expand

Data sheet

Released: 2024-02-13
Type: Cumulative update

Version	Build	Channel
21H2	19044.4046	General availability
22H2	19045.4046	General availability

Security

38 vulnerabilities fixed

3 exploited 1 critical 36 important 1 moderate

Vulnerability	Severity	CVSS
CVE-2024-21412 Exploited Internet Shortcut Files Security Feature Bypass Vulnerability	Important	8.1
CVE-2024-21338 Exploited Windows Kernel Elevation of Privilege Vulnerability	Important	7.8
CVE-2024-21351 Exploited Windows SmartScreen Security Feature Bypass Vulnerability	Moderate	7.6
CVE-2024-21357 Windows Pragmatic General Multicast (PGM) Remote Code Execution Vulnerability	Critical	8.1

The table lists the 4 exploited, publicly disclosed or critical vulnerabilities. See all 38 vulnerabilities →

Sources

Microsoft Support: KB5034763

Updated Oct 27, 2026

Cited passages from Microsoft's official notes (8)

1. This update addresses an issue that affects explorer.exe. It might stop responding. This occurs when you restart or shut down a PC that has a controller accessory attached to it. support.microsoft.com
2. This update addresses an issue that affects the Certificate Authority snap-in. You cannot select the "Delta CRL" option. This stops you from using the GUI to publish Delta CRLs. support.microsoft.com
3. This update addresses a known issue that might send you error 0xd0000034. This occurs when you try to upgrade some eligible devices to Windows 11 from Windows Update. support.microsoft.com
4. This build includes all the improvements from the supported Windows 10, version 21H2 editions. support.microsoft.com
5. This update addresses an issue that affects the download of device metadata. Downloads from the Windows Metadata and Internet Services (WMIS) over HTTPS are now more secure. support.microsoft.com
6. This update makes quality improvements to the servicing stack, which is the component that installs Windows updates. support.microsoft.com
7. This issue is addressed in KB5040525. support.microsoft.com
8. We are gradually rolling out a new Copilot experience for devices with KB5039299 or later updates installed. This new experience will address this issue. support.microsoft.com

Checked automatically: 7 of 8 checks passed, 8 quoted passages · compared with Microsoft's page on Nov 8, 2026

Quotes found in the official pages: passed
Numbers found in the sources: passed
Vulnerabilities from the dossier only: passed
Links to allowed domains only: passed
Every official change covered: passed
Readable plain text: passed
Changes confirmed by the file list: passed
Sources agree: not passed

A second AI read the text against the sources: correctness 3/5, clarity 4/5, completeness 4/5. How we work

Published by The Update Bureau. Written with AI from Microsoft's own documents, checked by rules and a second AI. How we work · Report a mistake