Back to vendor advisories
Microsoft Security Response CenterCVE-2026-83906

Windows Shell Spoofing Vulnerability

HighVendor CVSS 6.5 / 10 1 CVE Published Oct 13, 2026 at 7:00 AM UTC

Summary

Incorrect implementation of authentication algorithm in Windows Shell allows an unauthorized attacker to perform spoofing over a network.

Products covered

  • Windows Server 2025 (Server Core installation)

  • Windows 11 Version 25H2 for ARM64-based Systems

  • Windows 11 Version 25H2 for x64-based Systems

  • Windows 11 Version 23H2 for ARM64-based Systems

  • Windows 11 Version 23H2 for x64-based Systems

  • Windows 11 Version 24H2 for ARM64-based Systems

  • Windows 11 Version 24H2 for x64-based Systems

  • Windows Server 2025

Show 4 more products
  • Windows 11 version 26H1 for x64-based Systems

  • Windows 11 Version 26H1 for ARM64-based Systems

  • Windows 11 Version 26H2 for ARM64-based Systems

  • Windows 11 Version 26H2 for x64-based Systems

Remediation

Install KB5126646. Install KB5127648. Install KB5126653. Install KB5127646.

Vendor-listed fixes

  • 10.0.26100.33650

  • 10.0.26200.9711

  • 10.0.22631.7652

  • 10.0.26100.9711

  • 10.0.28000.3231

  • 10.0.26300.9711

CVEs in this advisory 1

Updates

  1. Published by Microsoft Security Response Center

    The publication date reported by the vendor.

  2. Added to SecurityAlert

    We collected the advisory from the official source.

  3. Confirmed at the source

    Our collector saw this advisory during a later source check.