Applies to:

Microsoft .NET Framework 4.8

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

IMPORTANT Some customers who use Windows Server 2008 R2 SP1 and have activated their ESU multiple activation key (MAK) add-on before installing the January 14, 2020 updates might need to re-activate their key. Re-activation on the affected devices should only be required once.  For information on activation, see this blog post.

IMPORTANT WSUS scan cab files will continue to be available for Windows 7 SP1 and Windows Server 2008 R2 SP1. If you have a subset of devices running these operating systems without ESU, they might show as non-compliant in your patch management and compliance toolsets.

IMPORTANT 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.

IMPORTANT Starting on January 15, 2020, a full-screen notification will appear that describes the risk of continuing to use Windows 7 Service Pack 1 after it reaches end of support on January 14, 2020. The notification will remain on the screen until you interact with it. This notification will only appear on the following editions of Windows 7 Service Pack 1:

Note The notification will not appear on domain-joined machines or machines in kiosk mode.

IMPORTANT Starting in August, 2019, updates to .NET Framework 4.6 and above, for Windows Server 2008 R2 SP1, and Windows 7SP1, require SHA-2 Code signing support. Please make sure that you have all the latest Windows Updates before applying this update to avoid installation issues. For more detailed information about SHA-2 code signing support updates, please see KB 4474419.

Summary

A remote code execution vulnerability exists in .NET Framework software when the software fails to check the source markup of a file. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the current user. If the current user is logged on with administrative user rights, an attacker could take control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights. Exploitation of the vulnerability requires that a user open a specially crafted file with an affected version of .NET Framework. In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted file to the user and convincing the user to open the file. The security update addresses the vulnerability by correcting how .NET Framework checks the source markup of a file.

To learn more about the vulnerabilities, go to the following Common Vulnerabilities and Exposures (CVE).

A denial of service vulnerability exists when .NET Framework improperly handles web requests. An attacker who successfully exploited this vulnerability could cause a denial of service against a .NET Framework web application. The vulnerability can be exploited remotely, without authentication. A remote unauthenticated attacker could exploit this vulnerability by issuing specially crafted requests to the .NET Framework application. The update addresses the vulnerability by correcting how the .NET Framework web application handles web requests.

To learn more about the vulnerabilities, go to the following Common Vulnerabilities and Exposures (CVE).

Quality and reliability improvements

Winforms

- Addresses an issue with WinForms ComboBox control reinitialization in AD FS MMC UI.

- Adresses an issue getting accessible objects for PropertyGridView ComboBox property items - adding the verification for item existence and validity.

- Addresses an issue with interaction between WPF user control and hosting WinForms app when processing keyboard input.

Workflow

- Addresses an accessibility issue where text inside a Windows Workflow Foundation Visual Basic Editor would use the wrong colors in high contrast themes.

CLR1

- Addresses rare crashes that could occur if Server GC is enabled and a GC occurs while another thread is running NGen'ed code which is making the initial call into NGen'ed code in a 2nd module where one or more parameter types involve valuetypes defined in a 3rd module.

- Addresses crashes that could occur in certain scenarios involving hot-added CPUs and/or multi-group machines where per-group CPU count is not consistent across all groups

- Addresses rare crashes or deadlocks that could occur if a GC occurs while another thread is running NGen'ed code which is making the initial call into a static method within the same module where one or more parameter types involve type-forwarded valuetypes.

- Addresses rare crashes that could occur during the first call that native code makes into the managed portion of a mixed-mode DLL.


1 Common Language Runtime (CLR)

Known issues in this update

Symptom

This update does not install, and it returns either or both of the following error messages:

  • -2146762495

  • A required certificate is not within its validity period when verifying against the current system clock or the timestamp in the signed file.

Workaround

This issue has been corrected in the latest Security and Quality Rollup for .NET Framework. 

Additional information about this update

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

  • 4556399 Description of the Security and Quality Rollup for .NET Framework 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8 for Windows 7 SP1 and Windows Server 2008 R2 SP1 (KB4556399)

How to obtain and install the 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. 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. The Extended Security Updates (ESU) Licensing Preparation Package (KB4538483) released February 11, 2020. 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.

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 if you are an ESU customer.

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 7 Service Pack 1, Windows Server 2008 R2 Service Pack 1,Windows Embedded Standard 7 Service Pack 1, Windows Embedded POSReady 7

Classification: Security Updates

Restart requirement

You must 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, go to the following article in the Microsoft Knowledge Base:

20200512 Security update deployment information: May 12, 2020

Update removal information

Note We do not recommend that you remove any security update. To remove this update, use the Programs and Features item in Control Panel.

Update restart information

This update does not require a system restart after you apply it unless files that are being updated are locked or are being used.

Update replacement information

This update replaces previously released updates 4533095 and 4535102.

File information

The English (United States) version of this software update installs files that have the attributes that are listed in the following tables.

x86

File name

File version

File size

Date

Time

Aspnet_perf.dll

4.8.4075.0

43,800

29-Apr-2020

17:19

aspnet_wp.exe

4.8.4075.0

47,608

29-Apr-2020

17:19

clr.dll

4.8.4180.0

8,044,832

29-Apr-2020

17:19

clrjit.dll

4.8.4180.0

561,648

29-Apr-2020

17:19

mscordacwks.dll

4.8.4180.0

1,315,104

29-Apr-2020

17:19

mscordbi.dll

4.8.4180.0

1,196,320

29-Apr-2020

17:19

mscoreei.dll

4.8.4180.0

581,920

29-Apr-2020

17:19

mscorlib.dll

4.8.4180.0

5,678,576

29-Apr-2020

17:19

Placeholder.dll

4.8.4180.0

26,096

29-Apr-2020

17:19

VsVersion.dll

14.8.4180.0

19,232

29-Apr-2020

17:19

PenIMC2_v0400.dll

4.8.4180.0

107,504

29-Apr-2020

17:19

peverify.dll

4.8.4180.0

190,232

29-Apr-2020

17:19

PresentationCore.dll

4.8.4180.0

3,676,440

29-Apr-2020

17:19

PresentationFramework.dll

4.8.4180.0

6,271,264

29-Apr-2020

17:19

PresentationFramework-SystemData.dll

4.8.4180.0

25,376

29-Apr-2020

17:19

PresentationHost_v0400.dll

4.8.4180.0

241,648

29-Apr-2020

17:19

PresentationHost_v0400.dll.mui

4.8.4180.0

85,272

29-Apr-2020

17:19

PresentationNative_v0400.dll

4.8.4180.0

930,808

29-Apr-2020

17:19

ReachFramework.dll

4.8.4110.0

677,656

29-Apr-2020

17:19

ServiceMonikerSupport.dll

4.8.4180.0

32,272

29-Apr-2020

17:19

SMDiagnostics.dll

4.8.4180.0

73,880

29-Apr-2020

17:19

SOS.dll

4.8.4180.0

774,944

29-Apr-2020

17:19

System.Activities.dll

4.8.4180.0

1,534,312

29-Apr-2020

17:19

System.Activities.Presentation.dll

4.8.4180.0

2,127,136

29-Apr-2020

17:19

System.Core.dll

4.8.4180.0

1,556,832

29-Apr-2020

17:19

System.IdentityModel.dll

4.8.4180.0

1,094,504

29-Apr-2020

17:19

System.IdentityModel.Services.dll

4.8.4180.0

199,152

29-Apr-2020

17:19

System.Printing.dll

4.8.4110.0

399,640

29-Apr-2020

17:19

System.Runtime.Serialization.dll

4.8.4180.0

1,054,872

29-Apr-2020

17:19

System.ServiceModel.Channels.dll

4.8.4180.0

158,704

29-Apr-2020

17:19

System.ServiceModel.Discovery.dll

4.8.4180.0

309,024

29-Apr-2020

17:19

System.ServiceModel.dll

4.8.4180.0

6,389,336

29-Apr-2020

17:19

System.ServiceModel.Internals.dll

4.8.4180.0

254,096

29-Apr-2020

17:19

System.ServiceModel.WasHosting.dll

4.8.4180.0

40,736

29-Apr-2020

17:19

System.Web.ApplicationServices.dll

4.8.4075.0

71,512

29-Apr-2020

17:19

System.Web.Extensions.dll

4.8.4075.0

1,849,992

29-Apr-2020

17:19

System.Workflow.Activities.dll

4.8.4110.0

1,051,112

29-Apr-2020

17:19

System.Workflow.ComponentModel.dll

4.8.4110.0

1,557,272

29-Apr-2020

17:19

System.Workflow.Runtime.dll

4.8.4110.0

503,064

29-Apr-2020

17:19

System.dll

4.8.4001.0

3,560,496

29-Apr-2020

17:19

System.Web.dll

4.8.4075.0

5,416,728

29-Apr-2020

17:19

System.Windows.Controls.Ribbon.dll

4.8.4180.0

751,392

29-Apr-2020

17:19

System.Windows.Forms.dll

4.8.4180.0

5,921,848

29-Apr-2020

17:19

System.Xaml.dll

4.8.4180.0

640,056

29-Apr-2020

17:19

UIAutomationClient.dll

4.8.4180.0

178,464

29-Apr-2020

17:19

UIAutomationClientsideProviders.dll

4.8.4180.0

361,760

29-Apr-2020

17:19

UIAutomationProvider.dll

4.8.4180.0

49,648

29-Apr-2020

17:19

UIAutomationTypes.dll

4.8.4180.0

223,512

29-Apr-2020

17:19

webengine.dll

4.8.4075.0

26,904

29-Apr-2020

17:19

webengine4.dll

4.8.4075.0

572,184

29-Apr-2020

17:19

WindowsBase.dll

4.8.4180.0

1,306,392

29-Apr-2020

17:19

WindowsFormsIntegration.dll

4.8.4180.0

105,248

29-Apr-2020

17:19

WorkflowServiceHostPerformanceCounters.dll

4.8.4110.0

89,368

29-Apr-2020

17:19

WPFFontCache_v0400.exe.mui

4.8.4180.0

19,744

29-Apr-2020

17:19

WPFFontCache_v0400.exe

4.8.4180.0

27,472

29-Apr-2020

17:19

wpfgfx_v0400.dll

4.8.4180.0

1,626,608

29-Apr-2020

17:19

x64

File name

File version

File size

Date

Time

Aspnet_perf.dll

4.8.4075.0

49,432

29-Apr-2020

17:19

Aspnet_perf.dll

4.8.4075.0

43,800

29-Apr-2020

17:19

aspnet_wp.exe

4.8.4075.0

53,032

29-Apr-2020

17:19

aspnet_wp.exe

4.8.4075.0

47,608

29-Apr-2020

17:19

clr.dll

4.8.4180.0

11,251,192

29-Apr-2020

17:19

clr.dll

4.8.4180.0

8,044,832

29-Apr-2020

17:19

clrjit.dll

4.8.4180.0

1,365,272

29-Apr-2020

17:19

clrjit.dll

4.8.4180.0

561,648

29-Apr-2020

17:19

compatjit.dll

4.8.4180.0

1,280,800

29-Apr-2020

17:19

mscordacwks.dll

4.8.4180.0

1,808,672

29-Apr-2020

17:19

mscordacwks.dll

4.8.4180.0

1,315,104

29-Apr-2020

17:19

mscordbi.dll

4.8.4180.0

1,662,752

29-Apr-2020

17:19

mscordbi.dll

4.8.4180.0

1,196,320

29-Apr-2020

17:19

mscoreei.dll

4.8.4180.0

689,952

29-Apr-2020

17:19

mscoreei.dll

4.8.4180.0

581,920

29-Apr-2020

17:19

mscorlib.dll

4.8.4180.0

5,439,264

29-Apr-2020

17:19

mscorlib.dll

4.8.4180.0

5,678,576

29-Apr-2020

17:19

VsVersion.dll

14.8.4180.0

19,232

29-Apr-2020

17:19

Placeholder.dll

4.8.4180.0

27,936

29-Apr-2020

17:19

Placeholder.dll

4.8.4180.0

26,096

29-Apr-2020

17:19

VsVersion.dll

14.8.4180.0

19,232

29-Apr-2020

17:19

PenIMC2_v0400.dll

4.8.4180.0

128,288

29-Apr-2020

17:19

PenIMC2_v0400.dll

4.8.4180.0

107,504

29-Apr-2020

17:19

peverify.dll

4.8.4180.0

273,184

29-Apr-2020

17:19

peverify.dll

4.8.4180.0

190,232

29-Apr-2020

17:19

PresentationCore.dll

4.8.4180.0

3,652,384

29-Apr-2020

17:19

PresentationCore.dll

4.8.4180.0

3,676,440

29-Apr-2020

17:19

PresentationFramework.dll

4.8.4180.0

6,271,264

29-Apr-2020

17:19

PresentationFramework-SystemData.dll

4.8.4180.0

25,376

29-Apr-2020

17:19

PresentationHost_v0400.dll

4.8.4180.0

310,048

29-Apr-2020

17:19

PresentationHost_v0400.dll.mui

4.8.4180.0

85,280

29-Apr-2020

17:19

PresentationHost_v0400.dll

4.8.4180.0

241,648

29-Apr-2020

17:19

PresentationHost_v0400.dll.mui

4.8.4180.0

85,272

29-Apr-2020

17:19

PresentationNative_v0400.dll

4.8.4180.0

1,171,744

29-Apr-2020

17:19

PresentationNative_v0400.dll

4.8.4180.0

930,808

29-Apr-2020

17:19

ReachFramework.dll

4.8.4110.0

677,656

29-Apr-2020

17:19

ServiceMonikerSupport.dll

4.8.4180.0

35,104

29-Apr-2020

17:19

ServiceMonikerSupport.dll

4.8.4180.0

32,272

29-Apr-2020

17:19

SMDiagnostics.dll

4.8.4180.0

73,880

29-Apr-2020

17:19

SOS.dll

4.8.4180.0

929,056

29-Apr-2020

17:19

SOS.dll

4.8.4180.0

774,944

29-Apr-2020

17:19

System.Activities.dll

4.8.4180.0

1,534,312

29-Apr-2020

17:19

System.Activities.Presentation.dll

4.8.4180.0

2,127,136

29-Apr-2020

17:19

System.Core.dll

4.8.4180.0

1,556,832

29-Apr-2020

17:19

System.IdentityModel.dll

4.8.4180.0

1,094,504

29-Apr-2020

17:19

System.IdentityModel.Services.dll

4.8.4180.0

199,152

29-Apr-2020

17:19

System.Printing.dll

4.8.4110.0

400,152

29-Apr-2020

17:19

System.Printing.dll

4.8.4110.0

399,640

29-Apr-2020

17:19

System.Runtime.Serialization.dll

4.8.4180.0

1,054,872

29-Apr-2020

17:19

System.ServiceModel.Channels.dll

4.8.4180.0

158,704

29-Apr-2020

17:19

System.ServiceModel.Discovery.dll

4.8.4180.0

309,024

29-Apr-2020

17:19

System.ServiceModel.dll

4.8.4180.0

6,389,336

29-Apr-2020

17:19

System.ServiceModel.Internals.dll

4.8.4180.0

254,096

29-Apr-2020

17:19

System.ServiceModel.WasHosting.dll

4.8.4180.0

40,736

29-Apr-2020

17:19

System.Web.ApplicationServices.dll

4.8.4075.0

71,512

29-Apr-2020

17:19

System.Web.Extensions.dll

4.8.4075.0

1,849,992

29-Apr-2020

17:19

System.Workflow.Activities.dll

4.8.4110.0

1,051,112

29-Apr-2020

17:19

System.Workflow.ComponentModel.dll

4.8.4110.0

1,557,272

29-Apr-2020

17:19

System.Workflow.Runtime.dll

4.8.4110.0

503,064

29-Apr-2020

17:19

System.dll

4.8.4001.0

3,560,496

29-Apr-2020

17:19

System.Web.dll

4.8.4075.0

5,403,624

29-Apr-2020

17:19

System.Web.dll

4.8.4075.0

5,416,728

29-Apr-2020

17:19

System.Windows.Controls.Ribbon.dll

4.8.4180.0

751,392

29-Apr-2020

17:19

System.Windows.Forms.dll

4.8.4180.0

5,921,848

29-Apr-2020

17:19

System.Xaml.dll

4.8.4180.0

640,056

29-Apr-2020

17:19

UIAutomationClient.dll

4.8.4180.0

178,464

29-Apr-2020

17:19

UIAutomationClientsideProviders.dll

4.8.4180.0

361,760

29-Apr-2020

17:19

UIAutomationProvider.dll

4.8.4180.0

49,648

29-Apr-2020

17:19

UIAutomationTypes.dll

4.8.4180.0

223,512

29-Apr-2020

17:19

webengine.dll

4.8.4075.0

28,952

29-Apr-2020

17:19

webengine.dll

4.8.4075.0

26,904

29-Apr-2020

17:19

webengine4.dll

4.8.4075.0

682,776

29-Apr-2020

17:19

webengine4.dll

4.8.4075.0

572,184

29-Apr-2020

17:19

WindowsBase.dll

4.8.4180.0

1,306,392

29-Apr-2020

17:19

WindowsFormsIntegration.dll

4.8.4180.0

105,248

29-Apr-2020

17:19

WorkflowServiceHostPerformanceCounters.dll

4.8.4110.0

102,672

29-Apr-2020

17:19

WorkflowServiceHostPerformanceCounters.dll

4.8.4110.0

89,368

29-Apr-2020

17:19

WPFFontCache_v0400.exe.mui

4.8.4180.0

19,744

29-Apr-2020

17:19

WPFFontCache_v0400.exe.mui

4.8.4180.0

19,744

29-Apr-2020

17:19

WPFFontCache_v0400.exe

4.8.4180.0

29,520

29-Apr-2020

17:19

WPFFontCache_v0400.exe

4.8.4180.0

27,472

29-Apr-2020

17:19

wpfgfx_v0400.dll

4.8.4180.0

2,058,016

29-Apr-2020

17:19

wpfgfx_v0400.dll

4.8.4180.0

1,626,608

29-Apr-2020

17:19

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