Overview of Windows 10 Update 19045.5794 (KB5055612)

Microsoft has rolled out the Windows 10 Release Preview build 19045.5794, identified as KB5055612, delivering important fixes that focus on improving GPU support and bolstering driver security. This update is part of the ongoing efforts by Microsoft to support Windows 10 users, particularly as the OS approaches its servicing end date on October 14, 2025.

Key Fixes in the Update

  • GPU Support Enhancement: The update resolves a case-sensitive issue in Windows Subsystem for Linux 2 (WSL2) which previously caused GPU paravirtualization support to fail. This fix is crucial for users leveraging GPU acceleration within WSL2 environments, ensuring smoother and more stable graphics processing capabilities.
  • Driver Security Upgrade: Microsoft has updated the Windows Kernel Vulnerable Driver Blocklist (DriverSiPolicy.p7b). This blocklist now includes drivers with known vulnerabilities that have been exploited in Bring Your Own Vulnerable Driver (BYOVD) attacks. By expanding this blocklist, Microsoft improves the kernel security model, preventing potentially malicious drivers from compromising the system.

Background Context

Windows 10 has been a cornerstone OS for millions of users worldwide. As its end of service nears, Microsoft continues to release cumulative updates focusing on both feature refinements and critical security patches. GPU paravirtualization in WSL2 is a relatively new technology enabling Linux environments on Windows to utilize GPU hardware for better performance in compute and graphics tasks.

BYOVD attacks target vulnerable or malicious drivers to elevate privileges or execute unauthorized code at the kernel level, posing significant security risks. The inclusion of more drivers in Microsoft's blocklist mitigates these risks by proactively blocking drivers known to be vulnerable or exploited.

Technical Details

  • The fix for the GPU support issue addresses a string comparison error in the GPU paravirtualization code path of WSL2 that was case-sensitive, thereby causing failures in recognizing GPU hardware resources correctly under certain circumstances.
  • The updated Kernel Vulnerable Driver Blocklist modifies the INLINECODE0 security policy file, restricting kernel-mode drivers identified as security liabilities from loading.

Implications and Impact

For enterprises and individual users relying on GPU-accelerated Linux workloads within WSL2, this update ensures greater reliability and performance stability.

Security-wise, expanding the driver blocklist strengthens system defense mechanisms against advanced persistent threats exploiting vulnerable drivers, which are a known attack vector in kernel-level exploits.

Given the proximity of Windows 10’s end of support, such updates signify Microsoft's commitment to safeguarding systems and providing compatibility improvements as users prepare for transition to newer operating systems like Windows 11.

How to Obtain the Update

Users enrolled in the Release Preview Channel can obtain this optional cumulative update via Windows Update with manual initiation. The update will also be available through the Microsoft Update Catalog for manual download.

Summary

KB5055612 continues Microsoft's dual focus on improving user experience by enhancing GPU support, particularly in Windows Subsystem for Linux, and reinforcing kernel security by blocking vulnerable drivers. These measures contribute to a more reliable and secure Windows 10 system as its support lifecycle progresses.