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Windows 11 and Server 2025 Update to Block Untrusted Cross

Cybersecuritynews •Abinaya • March 28, 2026

Microsoft is taking a major step to harden the Windows operating system against kernel-level threats by removing trust for drivers signed by the deprecated cross-signed root program. Starting with the April 2026 update, Windows 11 and Windows Server 2025 will block these untrusted drivers by default. This policy ensures that only drivers certified through the […]

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Microsoft Blocks Untrusted Kernel Drivers in Windows Update Microsoft is set to enhance Windows security by blocking kernel drivers signed by the deprecated cross-signed root program starting with the April 2026 update. This change affects Windows 11 and Windows Server 2025, where only drivers certified through the Windows Hardware Compatibility Program (WHCP) will be trusted. The decision aims to mitigate risks associated with legacy drivers that have not undergone recent security evaluations. While the policy will initially operate in 'evaluation mode' to assess compatibility issues, it signals a shift towards stricter security measures in the Windows ecosystem. Administrators can still allow custom drivers through specific policies, but this is intended for internal use rather than legacy support. Microsoft emphasizes the need for a balance between security and compatibility, acknowledging potential impacts on users reliant on older drivers. The change will apply to various Windows versions, including 24H2, 25H2, and 26H1. 2 sources 52

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Windows 11 Windows Server 2025