Note This release also contains updates for Microsoft HoloLens (OS Build 18362.1034) released October 8, 2019. Microsoft will release an update directly to the Windows Update Client to improve Windows Update reliability on Microsoft HoloLens that have not updated to this most recent OS Build.
ePub support ending in Microsoft Edge
Microsoft Edge will end support for e-books that use the .epub file extension over the next several months. For more information, see Download an ePub app to keep reading e-books.
- Updates to improve security when using Internet Explorer and Microsoft Edge.
- Updates for verifying user names and passwords.
- Updates for storing and managing files.
Improvements and fixes
This security update includes quality improvements. Key changes include:
- Addresses an issue in security bulletin CVE-2019-1318 that may cause client or server computers that don’t support Extended Master Secret (EMS) RFC 7627 to have increased connection latency and CPU utilization. This issue occurs while performing full Transport Layer Security (TLS) handshakes from devices that don’t support EMS, especially on servers. EMS support has been available for all the supported versions of Windows since calendar year 2015 and is being incrementally enforced by the installation of the October 8, 2019 and later monthly updates.
- Security updates to Windows Shell, Internet Explorer, Microsoft Edge, Windows App Platform and Frameworks, Windows Cryptography, Windows Authentication, Windows Storage and Filesystems, Windows Kernel, Microsoft Scripting Engine, and Windows Server.
If you installed earlier updates, only the new fixes contained in this package will be downloaded and installed on your device.
For more information about the resolved security vulnerabilities, please refer to the Security Update Guide.
Windows Update Improvements
Microsoft 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 doesn't apply to long-term servicing editions.
Known issues in this update
When setting up a new Windows device during the Out of Box Experience (OOBE), you might be unable to create a local user when using Input Method Editor (IME). This issue might affect you if you are using the IME for Chinese, Japanese, or Korean languages.Note This issue does not affect using a Microsoft Account during OOBE.
This issue is resolved in KB4530684.
Updates for Windows released October 8, 2019 or later provide protections, tracked by CVE-2019-1318, against an attack that could allow unauthorized access to information or data within TLS connections. This type of attack is known as a man-in-the-middle exploit. Windows might fail to connect to TLS clients and servers that do not support Extended Master Secret for resumption (RFC 7627). Lack of RFC support might cause one or more of the following errors or logged events:
|For information, see KB4528489.|
How to get this update
Before installing this update
Microsoft strongly recommends you install the latest servicing stack update (SSU) for your operating system before installing the latest cumulative update (LCU). SSUs improve the reliability of the update process to mitigate potential issues while installing the LCU and applying Microsoft security fixes. For more information, see Servicing stack updates.
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.|
|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 synchronize with WSUS if you configure Products and Classifications as follows:
Product: Windows 10, version 1903 and laterClassification: Security Updates
For a list of the files that are provided in this update, download the file information for cumulative update 4517389.