KB5075912 is a February 10, 2026 security update that patches critical vulnerabilities in Windows 10 versions 21H2 and 22H2. This update addresses security flaws in the Windows kernel, networking stack, and authentication mechanisms across x86, x64, and ARM64 architectures.
KB5075912Windows UpdateWindows
KB5075912 — February 2026 Security Update for Windows 10
KB5075912 is a February 2026 security update that addresses multiple vulnerabilities in Windows 10 versions 21H2 and 22H2, including critical fixes for Windows kernel and networking components.
Emanuel DE ALMEIDAKB5075912 is a February 2026 security update that addresses multiple vulnerabilities in Windows 10 versions 21H2 and 22H2, including critical fixes for Windows kernel and networking components.
Overview
In This Article
- Issue Description
- Root Cause
- 1Patches Windows kernel privilege escalation vulnerabilities
- 2Fixes authentication bypass in Windows networking protocols
- 3Resolves memory disclosure vulnerabilities in system services
- 4Strengthens Windows Defender integration and security scanning
- 5Updates security baselines and compliance frameworks
- Installation
- Known Issues
- Frequently Asked Questions
Applies to
Windows 10 Version 21H2 (all architectures)Windows 10 Version 22H2 (all architectures)
Issue Description
Issue Description
This security update addresses multiple vulnerabilities that could allow attackers to:
- Execute arbitrary code with elevated privileges through kernel exploitation
- Bypass authentication mechanisms in network protocols
- Perform denial-of-service attacks against Windows networking components
- Access sensitive information through memory disclosure vulnerabilities
- Escalate privileges through improper validation of user input
Systems without this update remain vulnerable to these security threats, particularly in enterprise environments with network exposure.
Root Cause
Root Cause
The vulnerabilities stem from improper input validation in Windows kernel components, insufficient bounds checking in networking protocols, and inadequate memory management in authentication services. These issues exist in the core Windows architecture and affect multiple system components including the kernel, network stack, and security subsystems.
1
Patches Windows kernel privilege escalation vulnerabilities
This update resolves multiple kernel-level vulnerabilities that could allow local attackers to escalate privileges. The fixes include improved input validation in system calls, enhanced memory protection mechanisms, and stricter access controls for kernel objects. These changes prevent unauthorized code execution in kernel mode and strengthen the security boundary between user and kernel space.
2
Fixes authentication bypass in Windows networking protocols
Addresses critical authentication weaknesses in Windows networking components that could allow remote attackers to bypass security controls. The update implements stronger validation of network authentication tokens, improves certificate verification processes, and enhances protocol-level security checks. These modifications prevent unauthorized network access and strengthen remote authentication mechanisms.
3
Resolves memory disclosure vulnerabilities in system services
Fixes information disclosure vulnerabilities where sensitive data could be leaked through improper memory handling in Windows system services. The update includes improved memory initialization routines, enhanced buffer management, and stricter memory access controls. These changes prevent unauthorized access to sensitive information stored in system memory.
4
Strengthens Windows Defender integration and security scanning
Enhances Windows Defender's ability to detect and prevent exploitation of the patched vulnerabilities. The update includes updated threat detection signatures, improved behavioral analysis capabilities, and enhanced real-time protection mechanisms. These improvements provide additional layers of security against both known and unknown threats.
5
Updates security baselines and compliance frameworks
Implements updated security baselines that align with current cybersecurity best practices and compliance requirements. The update includes revised security policies, updated audit configurations, and enhanced logging capabilities for security events. These changes help organizations maintain compliance with security standards and improve incident response capabilities.
Installation
Installation
KB5075912 is delivered automatically through Windows Update on February 10, 2026, as part of the monthly security update cycle. The update is classified as Important and will be installed automatically on systems with automatic updates enabled.
Installation Methods
- Windows Update: Available immediately on February 10, 2026
- Microsoft Update Catalog: Manual download available for offline installation
- WSUS/SCCM: Available for enterprise deployment through Windows Server Update Services
- Microsoft Intune: Deployable through cloud-based device management
Prerequisites
No specific prerequisites are required for this update. However, systems should have sufficient disk space (approximately 1.2 GB) and be running a supported version of Windows 10.
Installation Details
- File Size: Varies by architecture (800 MB - 1.2 GB)
- Restart Required: Yes, system restart is required to complete installation
- Installation Time: 15-30 minutes depending on system configuration
- Supersedes: Previous monthly security updates for Windows 10
Known Issues
Known Issues
Microsoft has identified the following issues that may occur after installing KB5075912:
Installation Failures
- Error 0x80070643: Installation may fail on systems with insufficient disk space. Ensure at least 2 GB of free space is available on the system drive before installation.
- Error 0x800f0922: May occur on systems with corrupted Windows Update components. Run
sfc /scannowandDISM /Online /Cleanup-Image /RestoreHealthbefore retrying installation.
Post-Installation Issues
- Network Connectivity: Some users may experience temporary network connectivity issues after restart. This typically resolves within 5-10 minutes as network services reinitialize.
- Third-Party Antivirus: Certain third-party antivirus solutions may require updates to maintain compatibility with the security enhancements. Contact your antivirus vendor for compatibility updates.
- Legacy Applications: Applications that rely on deprecated security APIs may experience compatibility issues. Test critical applications after installation and contact software vendors for updates if needed.
Workarounds
For systems experiencing network connectivity issues, restart the Windows networking services using the following PowerShell commands run as administrator:
Restart-Service -Name "Netlogon" -Force
Restart-Service -Name "Workstation" -Force
Restart-Service -Name "Server" -ForceOverview
KB5075912 is a critical security update released on February 10, 2026, addressing multiple high-severity vulnerabilities in Windows 10 versions 21H2 and 22H2. This update is part of Microsoft's monthly security update cycle and includes patches for vulnerabilities in the Windows kernel, networking protocols, and authentication mechanisms.
The update applies to all supported architectures of Windows 10, including 32-bit (x86), 64-bit (x64), and ARM64-based systems. Organizations should prioritize the deployment of this update due to the critical nature of the security vulnerabilities addressed.
Affected Systems
This security update applies to the following Windows 10 versions and builds:
| Operating System | Version | Build Before Update | Build After Update |
|---|---|---|---|
| Windows 10 | 21H2 | 19044.xxxx | 19044.6937 |
| Windows 10 | 22H2 | 19045.xxxx | 19045.6937 |
All architectures are supported:
- 32-bit Systems (x86)
- 64-bit Systems (x64)
- ARM64-based Systems
Security Vulnerabilities Addressed
This update addresses multiple security vulnerabilities across different Windows components:
Kernel-Level Vulnerabilities
Several critical vulnerabilities in the Windows kernel have been patched, including issues that could allow local privilege escalation and arbitrary code execution. These vulnerabilities primarily affect the kernel's handling of system calls and memory management routines.
Network Protocol Security
The update includes fixes for authentication bypass vulnerabilities in Windows networking protocols. These issues could potentially allow remote attackers to gain unauthorized access to network resources or intercept sensitive communications.
Memory Management Issues
Multiple information disclosure vulnerabilities related to improper memory handling have been resolved. These issues could allow attackers to access sensitive information from system memory, potentially compromising user credentials or other confidential data.
Installation Requirements
System Requirements
- Supported Windows 10 version (21H2 or 22H2)
- Minimum 2 GB free disk space
- Administrative privileges for installation
- Active internet connection for Windows Update delivery
Enterprise Deployment
Enterprise administrators can deploy this update through various channels:
- Windows Server Update Services (WSUS): Configure automatic approval for security updates
- System Center Configuration Manager (SCCM): Deploy through software update management
- Microsoft Intune: Push updates to managed devices through cloud-based management
- Group Policy: Configure automatic update policies for domain-joined systems
Verification and Validation
After installation, administrators can verify the update using several methods:
PowerShell Verification
Get-HotFix -Id KB5075912System Information
Check the build number in System Information (msinfo32.exe) to confirm the system is running build 19044.6937 or 19045.6937.
Windows Update History
Review Windows Update history in Settings > Update & Security > Windows Update > View update history to confirm successful installation.
Security Impact Assessment
The vulnerabilities addressed by KB5075912 pose significant security risks:
- High Impact: Kernel vulnerabilities could allow complete system compromise
- Network Exposure: Authentication bypass issues affect network security
- Data Protection: Memory disclosure vulnerabilities threaten data confidentiality
- Compliance: Unpatched systems may violate security compliance requirements
Rollback Considerations
While this is a security update, organizations may need to consider rollback procedures in case of compatibility issues:
- Updates can be uninstalled through Settings > Update & Security > Windows Update > View update history
- System Restore points are created automatically before installation
- Enterprise environments should test updates in non-production environments first
- Critical systems may require maintenance windows for update deployment
Long-Term Support Impact
This update is particularly important for organizations using Windows 10 versions approaching end-of-support:
- Windows 10 21H2 reaches end-of-support in June 2026
- Organizations should plan migration to newer Windows versions
- Security updates will continue until end-of-support dates
- Extended Security Updates may be available for enterprise customers
Frequently Asked Questions
What does KB5075912 resolve?
KB5075912 resolves multiple critical security vulnerabilities in Windows 10, including kernel privilege escalation issues, authentication bypass vulnerabilities in networking protocols, and memory disclosure problems in system services. The update strengthens Windows security across multiple components and prevents various attack vectors.
Which systems require KB5075912?
KB5075912 is required for all Windows 10 systems running versions 21H2 and 22H2, including 32-bit (x86), 64-bit (x64), and ARM64-based architectures. The update applies to builds 19044.xxxx and 19045.xxxx, updating them to builds 19044.6937 and 19045.6937 respectively.
Is KB5075912 a security update?
Yes, KB5075912 is a critical security update that addresses multiple high-severity vulnerabilities. It is part of Microsoft's monthly security update cycle and should be installed immediately to protect systems from potential security threats including privilege escalation, authentication bypass, and information disclosure attacks.
What are the prerequisites for KB5075912?
KB5075912 requires a supported Windows 10 version (21H2 or 22H2), at least 2 GB of free disk space, and administrative privileges for installation. No specific prior updates are required, but systems should have Windows Update components functioning properly for successful installation.
Are there known issues with KB5075912?
Known issues include potential installation failures due to insufficient disk space (error 0x80070643), temporary network connectivity issues after restart, and possible compatibility problems with third-party antivirus software. Most issues resolve automatically, but workarounds are available for persistent problems.
References (3)
1
10 février 2026—KB5075912 (Versions du système d'exploitation 19045.6937 et 19044.6937)Article de support officiel de Microsoft pour KB5075912 avec des informations complètes sur l'installation et le dépannagehttps://support.microsoft.com/en-us/topic/february-10-2026-kb5075912-os-builds-19045-6937-and-19044-6937-df558259-6b48-41ef-8601-6e75bb790e0e
2Historique des mises à jour de Windows 10Historique complet des mises à jour de Windows 10, y compris les correctifs de sécurité et les mises à jour de fonctionnalités.https://support.microsoft.com/en-us/topic/windows-10-update-history
3Centre de réponse de sécurité MicrosoftDernières recommandations de sécurité et informations sur les vulnérabilités de Microsofthttps://msrc.microsoft.com/
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