KB5082063 — April 2026 Security Update for Windows 11 24H2 and Windows Server 2025

Overview

KB5082063 is a critical security update released on April 14, 2026, for Windows 11 Version 24H2 and Windows Server 2025. This update addresses multiple high-severity vulnerabilities that could allow attackers to execute arbitrary code, gain elevated privileges, or bypass security features. The update brings affected systems to Build 26100.32690 and includes comprehensive security improvements across kernel-mode drivers, network protocols, graphics components, virtualization infrastructure, and authentication services.

Security Vulnerabilities Addressed

This security update resolves five critical vulnerabilities identified by Microsoft Security Response Center:

Kernel-Mode Driver Vulnerabilities (CVE-2026-0847, CVE-2026-0848)

Two separate vulnerabilities in kernel-mode drivers could allow local attackers to escalate privileges to SYSTEM level. These vulnerabilities affect display drivers and system service drivers that process user-mode requests without proper input validation. Successful exploitation could result in complete system compromise.

TCP/IP Stack Remote Code Execution (CVE-2026-0849)

A critical vulnerability in the Windows TCP/IP stack allows remote attackers to execute arbitrary code by sending specially crafted network packets. This vulnerability affects all network-connected Windows systems and could be exploited without user interaction.

Graphics Component Information Disclosure (CVE-2026-0850)

An information disclosure vulnerability in Windows Graphics Components could allow attackers to read sensitive memory contents, potentially exposing cryptographic keys, passwords, or other confidential data stored in system memory.

Hyper-V Security Feature Bypass (CVE-2026-0851)

A security feature bypass in Windows Hyper-V could allow guest virtual machines to escape isolation boundaries and access host system resources. This vulnerability primarily affects Windows Server 2025 systems running virtualized workloads.

Windows Authentication Elevation of Privilege (CVE-2026-0852)

An elevation of privilege vulnerability in Windows Authentication services could allow attackers to gain unauthorized access to domain resources by manipulating authentication tokens.

Affected Systems

This update applies to the following Windows versions:

Installation and Deployment

Organizations should prioritize the deployment of KB5082063 due to the critical nature of the vulnerabilities addressed. The update is compatible with all standard Windows deployment methods and can be integrated into existing patch management workflows.

Automatic Installation

Windows Update will automatically download and install this security update on consumer and small business systems. The installation typically occurs during scheduled maintenance windows or when users manually check for updates.

Enterprise Deployment Considerations

Enterprise environments should test this update in non-production environments before widespread deployment. Pay particular attention to systems running:

• Custom kernel-mode drivers
• Legacy network applications
• Hyper-V virtualization workloads
• Domain-joined systems with complex authentication requirements

Verification Commands

After installation, verify the update using PowerShell:

Get-HotFix -Id KB5082063
Get-ComputerInfo | Select WindowsBuildLabEx

The build number should show 26100.32690 after successful installation.

Security Impact and Recommendations

The vulnerabilities addressed in KB5082063 represent significant security risks that could lead to complete system compromise. Organizations should treat this as a critical update and deploy it as soon as possible after appropriate testing.

Post-Installation Considerations

After installing KB5082063, administrators should:

• Monitor system performance, particularly on Hyper-V hosts
• Test critical applications, especially those using network protocols
• Verify that custom drivers continue to function correctly
• Update security monitoring tools to recognize the new build number

The security improvements in this update may require adjustments to some applications or configurations, but these changes are necessary to maintain system security against current threats.