KB5034770: This update addresses a memory leak in ctfmon.exe

Improvements

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

• This update addresses an issue that affects remote direct memory access (RDMA) performance counters. They do not return networking data on VMs in the right way.
• This update addresses an issue that affects fontdrvhost.exe. It stops responding when you use Compact Font Format version 2 (CFF2) fonts.
• This update addresses a memory leak in ctfmon.exe.
• This update addresses a memory leak in TextInputHost.exe.
• This update addresses an issue that affects protected content. It stops cross-process windows from being created. Because of this update, you can keep using out-of-process hosting for things like WebView2 under protected, top-level windows.
• This update addresses an issue that affects touchscreens. They do not work properly when you use more than one monitor.
• This update addresses an issue that affects Windows Defender Application Control (WDAC). Its “allow” policies might block some binaries from running.
• This update affects Unified Extensible Firmware Interface (UEFI) Secure Boot systems. It adds a renewed signing certificate to the Secure Boot DB variable. You can now opt for this change.
• 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.
• This update addresses an issue that affects the Local Security Authority Subsystem Service (LSASS). It might stop working. This occurs when you access the Active Directory database.
• This update includes quarterly changes to the Windows Kernel Vulnerable Driver Blocklist file, DriverSiPolicy.p7b. It adds to the list of drivers that are at risk for Bring Your Own Vulnerable Driver (BYOVD) attacks.
• 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.
• This update addresses an issue that affects a local account. You cannot sign in to an account that Windows LAPS manages. This occurs if you set the "Require Smart Card for Interactive Logon" policy.
• This update addresses an issue that affects Server Message Block (SMB) connections. They disconnect when all of the following are true:
• You change the client and server encryption cipher list from the default values.
• The client and server do not have any ciphers in common.
• SMB encryption is not in use.
• A multi-channel configuration, such as RDMA, is in place.
• The update addresses an issue that affects SMB over a Quick UDP Internet Connection (QUIC). It stops responding if port 445 is blocked.
• This update changes a setting in Active Directory Users & Computers. By default, the snap-in now uses a strong certificate mapping of X509IssuerSerialNumber. It does not use the weak mapping of x509IssuerSubject.

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 and the February 2024 Security Updates.

Known issues

• After you install KB5034129, chromium-based internet browsers, such as Microsoft Edge, might not open correctly. Browsers affected by this issue might display a white screen and become unresponsive when you open them.
  Devices that have browser specific Image File Execution Options (IFEO) might be affected by this issue. When an entry for Microsoft Edge (msedge.exe) or other chromium-based browsers is found in the Windows registry, the issue might occur. A registry entry can be created by developer tools or when certain debugging and diagnostic settings are in place for browsers.
• Workaround
  You can prevent this issue by removing certain keys related to Image File Execution Options in the Windows registry.

Important This article contains information about how to modify the registry. Make sure that you back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, see How to back up and restore the registry in Windows.
Modify the Windows registry using the steps below.
Open the Windows Registry Editor. Open the Windows start menu and type regedit. Select Registry Editor from the results.
Go to the registry location Computer\\HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Image File Execution Options\\. Type this location in the path field that is below the File menu or use the left-side panel of the editor to find that path. Expand this path in the editor.
At that location, find the registry key related to the browser that is in use (denoted with a folder icon). Examples of the key name include msedge.exe for Microsoft Edge or chrome.exe. Click the key.
Examine the right-side panel that contains values associated with the key.
If the right-side panel only includes a value titled “(Default)”, it should be safe to remove the registry key. Right-click the key in the left-side panel of the editor and select Delete. After this, restart the device. This should address the issue, and the browser should open as expected.
If the right-side panel contains several values in addition to the one titled “(Default)”, it is still possible to address the issue by removing the registry key for this browser and restarting the device. However, note that doing so might remove configurations associated with the opening or starting process of the browser.
We are working on a resolution and will provide an update in an upcoming release.