KB5066873: Overview with user sentiment and feedback

Overview

This is a cumulative security update for Windows Server 2012 R2 that includes fixes and quality improvements. It addresses a stability issue observed in rare cases after installing previous security updates, causing some devices to become unresponsive. The update also removes the ltmdm64.sys driver, meaning fax modem hardware dependent on this driver will no longer work. Additionally, the update enforces a security hardening improvement by requiring the use of Key Storage Provider (KSP) instead of Cryptographic Service Provider (CSP) for RSA-based smart card certificates. This may impact smart card authentication in some cases. Finally, the update automatically disables the file preview feature in File Explorer for files downloaded from the internet, enhancing security by preventing a vulnerability.

General Purpose

The main purpose of this cumulative security update is to address stability issues, remove an outdated fax modem driver, enforce stronger cryptography requirements, and enhance security by disabling risky file previews. The stability fix addresses an issue causing some devices to become unresponsive after installing previous updates. The cryptography change aims to improve security by requiring a more secure key storage method. And the file preview disable helps prevent potential vulnerabilities when users preview downloaded files. Overall, this update includes important security and quality improvements for Windows Server 2012 R2 users.

General Sentiment

The general sentiment around this update appears mixed. On the positive side, it addresses some important stability and security issues that have impacted Windows Server 2012 R2 users. The cryptography change and file preview disable are welcome security enhancements. However, the removal of the fax modem driver may cause disruption for some organizations still relying on that functionality. Additionally, the cryptography change could potentially cause authentication problems for smart card users, requiring them to take additional steps to resolve. Overall, the update seems to provide more benefits than drawbacks, but there are a few areas that may cause some user frustration or require mitigation efforts.

Known Issues

• The installation of this Extended Security Update (ESU) might fail when trying to install it on an Azure Arc-enabled device running Windows Server 2012 R2. To successfully install, make sure all Subset of endpoints for ESU only are met as described in Connected Machine agent network requirements.- The cryptography change requiring use of Key Storage Provider (KSP) instead of Cryptographic Service Provider (CSP) for RSA-based smart card certificates may cause problems with smart card authentication. Users experiencing issues should check the Windows Release Health site for resolution steps.

Disclaimer: We take measures to ensure that AI-generated content is of the highest possible quality, but we cannot guarantee its accuracy and recommend that users do their own independent research. Generated on 2025-11-30 01:17 AM

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