Applies To.NET

Revised July 30, 2024: Add breaking change information to known issue section. 

Applies to:

Microsoft .NET Framework 4.8

REMINDER Windows Server 2008 R2 SP1 have reached the end of mainstream support and are now in extended security update (ESU) support.

Starting in July 2020, there will no longer be optional, non-security releases (known as "C" releases) for this operating system. Operating systems in extended support have only cumulative monthly security updates (known as the "B" or Update Tuesday release).

Verify that you have installed the required updates listed in the How to get this update section before installing this update. 

Customers who have purchased the Extended Security Update (ESU) for on-premises versions of these operating systems must follow the procedures in KB4522133 to continue receiving security updates after extended support ends on January 14, 2020. For more information on ESU and which editions are supported, see KB4497181. For more information, see the ESU blog.

The July 9, 2024 update for Windows Server 2008 R2 SP1 includes security improvements in .NET Framework 4.8. We recommend that you apply this update as part of your regular maintenance routines. Verify that you have installed the required updates listed in the How to get this update section before installing this update.

Summary

CVE-2024-38081 - .NET Framework Elevation of Privilege Vulnerability This security update addresses a remote code execution vulnerability detailed in CVE-2024-38081.

Additional information about this update

The following articles contain additional information about this update as it relates to individual product versions.

  • 5041026 Description of the Security Only Update for .NET Framework 3.5.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8 for Windows Server 2008 R2 SP1 (KB5041026)

Known issues in this update

Breaking change details

The .NET Framework servicing update released on July 2024 security and quality rollup - .NET Framework contains a security fix addressed an elevation of privilege vulnerability detailed in CVE 2024-38081. The fix changed System.IO.Path.GetTempPath method return value. If windows version exposes the GetTempPath2 Win32 API, this method invokes that API and returns the resolved path. See the Remarks section of the GetTempPath2 documentation for more information on how this resolution is performed, including how to control the return value through the use of environment variables. The GetTempPath2 API may not be available on all versions of Windows.

Please reference to the System.IO.Path.GetTempPath API for more information.

Temporary workaround

⚠️ Warning: The opt-out will disable the security fix for the elevation of privilege vulnerability detailed in CVE 2024-38081. The opt-out is only for temporary workaround if you're sure that the software is running in secure environments. Microsoft does not recommend applying this temporary workaround.

Resolution

The API behavior change is by design to address the elevation of privilege vulnerability. Any affected software or application is expected to make code change to adapt to this new design change.

How to get this update

Before installing this update

Prerequisite:

To apply this update, you must have .NET Framework 4.8 installed.

You must install the updates listed below and restart your device before installing the latest Rollup. Installing these updates improves the reliability of the update process and mitigates potential issues while installing the Rollup and applying Microsoft security fixes.

  1. The March 12, 2019 servicing stack update (SSU) (KB4490628). To get the standalone package for this SSU, search for it in the Microsoft Update Catalog. This update is required to install updates that are only SHA-2 signed.

  2. The latest SHA-2 update (KB4474419) released September 10, 2019 or newer update. If you are using Windows Update, the latest SHA-2 update will be offered to you automatically. This update is required to install updates that are only SHA-2 signed. For more information on SHA-2 updates, see 2019 SHA-2 Code Signing Support requirement for Windows and WSUS.

  3. To get this security update, you must reinstall the "Extended Security Updates (ESU) Licensing Preparation Package" (KB5016892) for Windows Server 2008 R2 SP1 that is dated August 8, 2022 even if you previously installed the ESU key. The ESU licensing preparation package will be offered to you from WSUS. To get the standalone package for ESU licensing preparation package, search for it in the Microsoft Update Catalog.

  4. After you install the items above, we strongly recommend that you install the latest SSU.

    ​​​​​​​For Windows Server 2008 R2 SP1, you must have the servicing stack update (SSU) (KB5017397) that is dated September 13, 2022 or later installed. For more information about the latest SSU updates, see ADV990001 | Latest Servicing Stack Updates. If you use Windows Update, the latest SSU will be offered to you automatically if you are an ESU customer. To get the standalone package for the latest SSU, search for it in the Microsoft Update Catalog. For general information about SSUs, see Servicing stack updates and Servicing Stack Updates (SSU): Frequently Asked Questions.

  5. Download the ESU MAK add-on key from the VLSC portal and deploy and activate the ESU MAK add-on key. If you use the Volume Activation Management Tool  (VAMT) to deploy and activate keys, follow the instructions here.

    IMPORTANT You do not need an additional key for deployment of the following:

    • You do not need to deploy an additional ESU key for Azure virtual machines (VMs), Azure Stack HCI.

    • For other Azure products such as Azure VMWare, Azure Nutanix solution Azure Stack (Hub, Edge), or for bring-your-own images on Azure for Windows Server 2008 SP2, and Windows Server 2008 R2 SP1 you do need to deploy the ESU key.  The steps to install, activate, and deploy ESUs are the same for the fourth year of ESU coverage.

Install this update

Release Channel

Available

Next Step

Windows Update and Microsoft Update

No

See the other options below.

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 individual .NET Framework product update will be installed, as applicable, by applying the operating system update. For more information about operating system updates see additional information about this update section.

Restart requirement

You may need to restart the computer after you apply this update if any affected files are being used. We recommend that you exit all .NET Framework-based applications before you apply this update.

Update deployment information

For deployment details for this security update, see the Deployments tab of the Microsoft Security Response Center (MSRC) Security Update Guide.

File Information

x86

File name

File version

File size

Date

Time

vbc.exe

14.8.4739.0

2,619,472

13-Jun-2024

08:31

aspnet_regbrowsers.exe

4.8.4739.0

39,496

13-Jun-2024

08:31

aspnet_regiis.exe

4.8.4739.0

36,288

13-Jun-2024

08:31

aspnet_regsql.exe

4.8.4739.0

121,280

13-Jun-2024

08:31

clr.dll

4.8.4739.0

8,659,392

13-Jun-2024

08:31

clrjit.dll

4.8.4739.0

555,952

13-Jun-2024

08:31

mscordacwks.dll

4.8.4739.0

1,308,592

13-Jun-2024

08:31

mscordbi.dll

4.8.4739.0

1,189,296

13-Jun-2024

08:31

mscorlib.dll

4.8.4739.0

5,729,328

13-Jun-2024

08:31

mscorpehost.dll

4.8.4739.0

152,496

13-Jun-2024

08:31

peverify.dll

4.8.4739.0

183,840

13-Jun-2024

08:31

PresentationHost_v0400.dll

4.8.4739.0

234,944

13-Jun-2024

08:31

PresentationHost_v0400.dll.mui

4.8.4739.0

78,880

13-Jun-2024

08:31

SOS.dll

4.8.4739.0

768,928

13-Jun-2024

08:31

x64

File name

File version

File size

Date

Time

vbc.exe

14.8.4739.0

3,228,640

13-Jun-2024

08:51

vbc.exe

14.8.4739.0

2,619,472

13-Jun-2024

08:31

aspnet_regbrowsers.exe

4.8.4739.0

38,856

13-Jun-2024

08:51

aspnet_regbrowsers.exe

4.8.4739.0

39,496

13-Jun-2024

08:31

aspnet_regiis.exe

4.8.4739.0

41,920

13-Jun-2024

08:51

aspnet_regiis.exe

4.8.4739.0

36,288

13-Jun-2024

08:31

aspnet_regsql.exe

4.8.4739.0

120,880

13-Jun-2024

08:51

aspnet_regsql.exe

4.8.4739.0

121,280

13-Jun-2024

08:31

clr.dll

4.8.4739.0

11,710,896

13-Jun-2024

08:51

clr.dll

4.8.4739.0

8,659,392

13-Jun-2024

08:31

clrjit.dll

4.8.4739.0

1,359,392

13-Jun-2024

08:51

clrjit.dll

4.8.4739.0

555,952

13-Jun-2024

08:31

compatjit.dll

4.8.4739.0

1,274,288

13-Jun-2024

08:51

mscordacwks.dll

4.8.4739.0

1,803,800

13-Jun-2024

08:51

mscordacwks.dll

4.8.4739.0

1,308,592

13-Jun-2024

08:31

mscordbi.dll

4.8.4739.0

1,655,832

13-Jun-2024

08:51

mscordbi.dll

4.8.4739.0

1,189,296

13-Jun-2024

08:31

mscorlib.dll

4.8.4739.0

5,491,760

13-Jun-2024

08:51

mscorlib.dll

4.8.4739.0

5,729,328

13-Jun-2024

08:31

mscorpehost.dll

4.8.4739.0

188,848

13-Jun-2024

08:51

mscorpehost.dll

4.8.4739.0

152,496

13-Jun-2024

08:31

peverify.dll

4.8.4739.0

266,688

13-Jun-2024

08:51

peverify.dll

4.8.4739.0

183,840

13-Jun-2024

08:31

PresentationHost_v0400.dll

4.8.4739.0

304,048

13-Jun-2024

08:51

PresentationHost_v0400.dll.mui

4.8.4739.0

78,880

13-Jun-2024

08:51

PresentationHost_v0400.dll

4.8.4739.0

234,944

13-Jun-2024

08:31

PresentationHost_v0400.dll.mui

4.8.4739.0

78,880

13-Jun-2024

08:31

SOS.dll

4.8.4739.0

923,040

13-Jun-2024

08:51

SOS.dll

4.8.4739.0

768,928

13-Jun-2024

08:31

How to obtain help and support for this update

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