Today is the second Tuesday of the month, and you know what that means. It's Patch Tuesday, so as long as you're on a supported version of Windows, you're getting an update today. And if you're not on a supported version, well, you should be. For consumers, that includes Windows 10 version 1909 and up, and if you're on something earlier, Windows Update should be trying to push you to something newer.

If you're on Windows 10 version 20H2 or 2004, you're going to get KB4598242, bringing the build number to 19042.746 or 19041.746, respectively. You can manually download it here, and these are the highlights:

  • Updates to improve security when using external devices, such as game controllers, printers, and web cameras.
  • Updates to improve security when Windows performs basic operations.

Here's the full list of fixes:

  • Addresses a security vulnerability issue with HTTPS-based intranet servers. After installing this update, HTTPS-based intranet servers cannot, by default, use a user proxy to detect updates. Scans using these servers will fail if you have not configured a system proxy on the clients. If you must use a user proxy, you must configure the behavior using the policy “Allow user proxy to be used as a fallback if detection using system proxy fails.” To ensure the highest levels of security, also use Windows Server Update Services (WSUS) Transport Layer Security (TLS) certificate pinning on all devices. This change does not affect customers who are using HTTP WSUS servers. For more information, see Changes to scans, improved security for Windows devices.
  • Addresses a security bypass vulnerability that exists in the way the Printer Remote Procedure Call (RPC) binding handles authentication for the remote Winspool interface. For more information, see KB4599464.
  • Security updates to Windows App Platform and Frameworks, Windows Media, Windows Fundamentals, Windows Kernel, Windows Cryptography, Windows Virtualization, Windows Peripherals, and Windows Hybrid Storage Services.

There are also a couple of known issues:

Symptom Workaround

System and user certificates might be lost when updating a device from Windows 10, version 1809 or later to a later version of Windows 10. Devices will only be impacted if they have already installed any Latest cumulative update (LCU) released September 16, 2020 or later and then proceed to update to a later version of Windows 10 from media or an installation source which does not have an LCU released October 13, 2020 or later integrated. This primarily happens when managed devices are updated using outdated bundles or media through an update management tool such as Windows Server Update Services (WSUS) or Microsoft Endpoint Configuration Manager. This might also happen when using outdated physical media or ISO images that do not have the latest updates integrated.

Note Devices using Windows Update for Business or that connect directly to Windows Update are not impacted. Any device connecting to Windows Update should always receive the latest versions of the feature update, including the latest LCU, without any extra steps.

If you have already encountered this issue on your device, you can mitigate it within the uninstall window by going back to your previous version of Windows using the instructions here. The uninstall window might be 10 or 30 days depending on the configuration of your environment and the version you’re updating to. You will then need to update to the later version of Windows 10 after the issue is resolved in your environment. Note Within the uninstall window, you can increase the number of days you have to go back to your previous version of Windows 10 by using the DISM command /Set-OSUninstallWindow. You must make this change before the default uninstall window has lapsed. For more information, see DISM operating system uninstall command-line options.

We are working on a resolution and will provide updated bundles and refreshed media in the coming weeks.

When using the Microsoft Japanese Input Method Editor (IME) to enter Kanji characters in an app that automatically allows the input of Furigana characters, you might not get the correct Furigana characters. You might need to enter the Furigana characters manually.

Note The affected apps are using the ImmGetCompositionString() function.

We are working on a resolution and will provide an update in an upcoming release.

If you're on Windows 10 version 1909, you'll get KB4598229, bringing the build number to 18363.1316. Note that this update is not being released for version 1903, as support for that ended last month. You can manually download it here, and these are the highlights:

  • Updates to improve security when using external devices, such as game controllers, printers, and web cameras.
  • Updates to improve security when using Microsoft Office products.
  • Updates to improve security when Windows performs basic operations.

Here's the full list of fixes:

  • Addresses a security vulnerability issue with HTTPS-based intranet servers. After installing this update, HTTPS-based intranet servers cannot, by default, use a user proxy to detect updates. Scans using these servers will fail if you have not configured a system proxy on the clients. If you must use a user proxy, you must configure the behavior using the policy “Allow user proxy to be used as a fallback if detection using system proxy fails.” To ensure the highest levels of security, also use Windows Server Update Services (WSUS) Transport Layer Security (TLS) certificate pinning on all devices. This change does not affect customers who are using HTTP WSUS servers. For more information, see Changes to scans, improved security for Windows devices.
  • Addresses a security bypass vulnerability that exists in the way the Printer Remote Procedure Call (RPC) binding handles authentication for the remote Winspool interface. For more information, see KB4599464.
  • Addresses an issue that might damage the file system of some devices and prevent them from starting up after running chkdsk /f.
  • Security updates to Windows App Platform and Frameworks, Microsoft Graphics Component, Windows Media, Windows Fundamentals, Windows Kernel, Windows Cryptography, Windows Virtualization, Windows Peripherals, and Windows Hybrid Storage Services.

There's also one known issue to be aware of:

Symptom Workaround

System and user certificates might be lost when updating a device from Windows 10, version 1809 or later to a later version of Windows 10. Devices will only be impacted if they have already installed any Latest cumulative update (LCU) released September 16, 2020 or later and then proceed to update to a later version of Windows 10 from media or an installation source which does not have an LCU released October 13, 2020 or later integrated. This primarily happens when managed devices are updated using outdated bundles or media through an update management tool such as Windows Server Update Services (WSUS) or Microsoft Endpoint Configuration Manager. This might also happen when using outdated physical media or ISO images that do not have the latest updates integrated.

Note Devices using Windows Update for Business or that connect directly to Windows Update are not impacted. Any device connecting to Windows Update should always receive the latest versions of the feature update, including the latest LCU, without any extra steps.

If you have already encountered this issue on your device, you can mitigate it within the uninstall window by going back to your previous version of Windows using the instructions here. The uninstall window might be 10 or 30 days depending on the configuration of your environment and the version you’re updating to. You will then need to update to the later version of Windows 10 after the issue is resolved in your environment. Note Within the uninstall window, you can increase the number of days you have to go back to your previous version of Windows 10 by using the DISM command /Set-OSUninstallWindow. You must make this change before the default uninstall window has lapsed. For more information, see DISM operating system uninstall command-line options.

We are working on a resolution and will provide updated bundles and refreshed media in the coming weeks.

Below are the updates that are not available for general consumers, but are available for some SKUs.

Version KB Build Download Support
1809

KB4598230

17763.1697 Update Catalog Enterprise and Education SKUs
1803

KB4598245

17134.1967 Update Catalog
1703

KB4599208

15063.2614 Update Catalog Surface Hub only
1607

KB4598243

14393.4169 Update Catalog Long-Term Servicing Branch
1507

KB4598231

10240.18818 Update Catalog

As always, these updates are mandatory. That means that while you can install them through Windows Update, if you don't, they'll be installed automatically at some point.