August 14, 2018—KB4343885 (OS Build 15063.1266)

Note This release also contains updates for Windows 10 Mobile (OS Build 15063.1266) released August 14, 2018.

Improvements and fixes

This update includes quality improvements. No new operating system features are being introduced in this update. Key changes include:

• Provides protections against a new speculative execution side-channel vulnerability known as L1 Terminal Fault (L1TF) that affects Intel® Core® processors and Intel® Xeon® processors (CVE-2018-3620 and CVE-2018-3646). Make sure previous OS protections against Spectre Variant 2 and Meltdown vulnerabilities are enabled using the registry settings outlined in the Windows Client guidance KB article. (These registry settings are enabled by default for Windows Client OS editions.)
• Addresses an issue that causes Internet Explorer to stop working for certain websites.
• Updates support for the draft version of the Token Binding protocol v0.16.
• Addresses an issue that causes Device Guard to block some ieframe.dll class IDs after installing the May 2018 Cumulative Update.
• Ensures that Internet Explorer and Microsoft Edge support the preload=“none” tag.
• Addresses a vulnerability related to the Export-Modulemember() function when used with a wildcard (*) and a dot-sourcing script. After installing this update, existing modules on devices that have Device Guard enabled will intentionally fail. The exception error is “This module uses the dot-source operator while exporting functions using wildcard characters, and this is disallowed when the system is under application verification enforcement”. For more information, see https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8200 and https://aka.ms/PSModuleFunctionExport.
• Addresses an issue that was introduced in the July 2018 .NET Framework update. Applications that rely on COM components were failing to load or run correctly because of “access denied,” “class not registered,” or “internal failure occurred for unknown reasons” errors.
• Addresses a vulnerability issue by correcting the way that the .NET Framework handles high-load or high-density network connections. For more information, see CVE-2018-8360.
• Security updates to Windows Server.
  If you installed earlier updates, only the new fixes in this package will be downloaded and installed on your device.For more information about the resolved security vulnerabilities, see the Security Update Guide.

Windows Update ImprovementsMicrosoft has released an update directly to the Windows Update client to improve reliability. Any device running Windows 10 configured to receive updates automatically from Windows Update, including Enterprise and Pro editions, will be offered the latest Windows 10 Feature Update based on device compatibility and Windows Update for Business deferral policy. This does not apply to long-term servicing editions.

Known issues in this update

Microsoft is not currently aware of any issues with this update.

How to get this update

This update will be downloaded and installed automatically from Windows Update. To get the standalone package for this update, go to the Microsoft Update Catalog website.File informationFor a list of the files that are provided in this update, download the file information for cumulative update 4343885.