KB4594440, KB4594441 & KB4594443 – Windows 10 Out-of-band Updates

Microsoft has recently released an out-of-band update for Windows 10 1809 users installing which solves the bugs related to Kerberos authentication. On 19th Nov 2020, the company rolls this new update for other Windows 10 versions as well. Installing KB4594440 will increase Windows 10 20H1/20H2 build versions to 19041.631 and 19042.631 respectively.

Similarly, installing KB4594441 will increase Windows 10 1903/1909 build versions to 18362.1199 and 18363.1199 respectively. If you using Windows 10 version 1607, install KB4594441 and upgrade your PC to Build 14393.4048. 

Since this is an optional update, install only if you are facing the Kerberos authentication or ticket renewal issues. To know more, read CVE-2020-17049 in detail.

KB4594440

Windows 10 All versions Out-of-band Update

The key features of the Out-of-band update remain the same for all versions of Windows 10. Here is the complete changelog –

Microsoft has solved the Kerberos authentication issue with this out-of-band update. The problem was related to the PerformTicketSignature registry subkey value as elaborated on CVE-2020-17049. Besides this, the changes are as follows –

  • Non-Window Kerberos clients may also renew the related services and ticket-granting tickets (TGT). To do so, all they require is to change the PerformTicketSignature value to “1”.
  • When the PerformTicketSignature value is set to “1”, scheduled tasks, clustering, or some other services will simply fail for their respective clients.  
  • S4UProxy delegation might fail during ticket referral in cross-domain scenarios. This occurs only when the DCs are the intermediate domains and get updated irregularly keeping the PerformTicketSignature value fixed to “1”.
Quick Note: You will not encounter any new issues after installing the out-of-band update on your computer. The errors that were occurring on the respective Windows 10 version continue to exist. 

How to Download and Install KB4594440

As of now, the out-of-band updates are not available either via Windows Update or WSUS. If you want to install this patch on your computer, you may do so by downloading the standalone packages from Update Catalog. 

Reminder: Make sure to install the (KB4586864) servicing stack before following the below steps. 
  • Go to Microsoft’s official site, pick the update matching your system architecture, and hit the Download button.
  • Subsequently, click the top link to start downloading the KB4594440 update.
  • After the download finishes, head over to the folder containing this file.
  • Double-click upon the setup to install this out-of-band update on your computer. 
  • When the installation completes, you’re on either version 19041.631 or 19042.631.

How to Install KB4594441 and KB4594443

If you are on Windows 10 version 1607 or 1903/1909, use the links provided below –

Servicing Stack Updates

After downloading the latest SSU on your respective PCs, download the standalone packages from here –

Release Notes: 20H1/20H2, 1903/1909, 1607 

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