Notice

Revised 6/8/2021

On June 8th, 2021, this update was released to replace a previous update to address a “revocation server was offline” error that may occur during installation. If you've already installed a previous release of this update, no action is required. To obtain the latest version of these updates, see the "How to obtain and install the update" section of the individual update article.  Links to each article are found in the "Additional information about this update" section of this article.

On April 13th, 2021, this update was released to replace a previous release of this update.

On July 23, 2020, update KB4552952 v2 and KB4552951 v2 were released to replace v1 of those updates for .NET Framework 4.5.2 and 4.6 for Windows Server 2008 SP2. The v1 updates did not install for customers who had certain ESU configurations.  The v2 updates correct the issue for customers who could not install the v1 updates.  

Applies to:

Microsoft .NET Framework 2.0 Microsoft .NET Framework 3.0 Microsoft .NET Framework 4.5.2 Microsoft .NET Framework 4.6

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

IMPORTANT WSUS scan cab files will continue to be available for Windows Server 2008 SP2. If you have a subset of devices running this operating system 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 this OS 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 in August, 2019, updates to .NET Framework 4.6 and above, for Windows Server 2008 SP2 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.

IMPORTANT All updates for .NET Framework 4.7.2, 4.7.1, 4.7, 4.6.2, 4.6.1, and 4.6 require that the d3dcompiler_47.dll update is installed. We recommend that you install the included d3dcompiler_47.dll update before you apply this update. For more information about the d3dcompiler_47.dll, see KB 4019990.

IMPORTANT If you install a language pack after you install this update, you must reinstall this update. Therefore, we recommend that you install any language packs that you need before you install this update. For more information, see Add language packs to Windows.

Summary

An elevation of privilege vulnerability exists in .NET Framework which could allow an attacker to elevate their privilege level. To exploit the vulnerability, an attacker would first have to access the local machine, and then run a malicious program. The update addresses the vulnerability by correcting how .NET Framework activates COM objects.  

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

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).

Known issues in some parts of 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.

  • The revocation function was unable to check revocation because the revocation server was offline.

Workaround

This issue was corrected by the latest release of the affected parts in this update.

If you've already installed a previous release of the affected parts, no action is required.

Additional information about this update

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

  • 4552964 Description of the Security Only Update for .NET Framework 2.0, 3.0 for Windows Server 2008 SP2 (KB4552964)

  • 4552952 Description of the Security Only Update for .NET Framework 4.5.2 for Windows 7 SP1 and Windows Server 2008 R2 SP1 and Windows Server 2008 SP2 (KB4552952)

  • 4552951 Description of the Security Only Update for .NET Framework 4.6 for Windows 7 SP1 and Windows Server 2008 R2 SP1 and Windows Server 2008 SP2 (KB4552951)

Information about protection and security

Need more help?

Expand your skills
Explore Training
Get new features first
Join Microsoft Insiders

Was this information helpful?

What affected your experience?

Thank you for your feedback!

×