For January, Patch Tuesday starts off with a bang

After installing KB5074109, KB5073455, or KB5073724, users connecting to Azure Virtual Desktop or Windows 365 Cloud PCs via the Windows App could experience authentication errors and credential prompt failures. Microsoft is preparing an out-of-band fix. In the meantime, enterprise teams should direct affected users to connect via the Remote Desktop client for Windows (MSRDC) or the Windows App Web Client.

A small number of users might notice that the password icon on the Windows login screen is not visible. This has been an ongoing issue since the August 2025 update. Microsoft published a Known Issue Rollback (KIR) to address Pro and Home users. Enterprise deployments should use an updated Group Policy to restore the icon.

This update intentionally removes legacy Agere and Motorola soft modem drivers (agrsm64.sys, agrsm.sys, smserl64.sys, smserial.sys) to address CVE-2023-31096, an elevation of privilege vulnerability. Notably, the mere presence of these drivers — even without a modem connected — rendered systems vulnerable. Hardware dependent on these drivers will no longer function after applying the January updates.

As we noted in December, the 2011 certificates currently used by most Windows devices will begin expiring in June, with a second batch expiring this coming October. Devices that do not receive the updated 2023 certificates could fail to boot securely or stop receiving future Secure Boot security fixes.

Resolved issues

This is a new section to our monthly rundown. Depending on future Microsoft updates, this section may evolve or get integrated in platform specific sections. The January release resolves several issues that had been affecting enterprise environments:

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AndyC

Andy Curtis is an award-winning security consultant, researcher and public speaker. He has been working in the computer security industry since the early 1990s, having been employed by state and federal government, leading healthcare and banking providers across three continents. He has given talks about computer security for some of the world’s largest companies, worked with law enforcement agencies on investigations into hacking groups, and is a regular voice on TV and radio explaining IT security threats.

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