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Microsoft Security Response CenterCVE-2026-70005

Active Directory Federation Services (AD FS) Security Feature Bypass Vulnerability

HighVendor CVSS 5.9 / 10 1 CVE Published Oct 13, 2026 at 7:00 AM UTC

Summary

Weak authentication in Active Directory Federation Services (AD FS) allows an unauthorized attacker to bypass a security feature over a network.

Products covered

  • Windows Server 2019

  • Windows Server 2019 (Server Core installation)

  • Windows Server 2022

  • Windows Server 2022 (Server Core installation)

  • Windows Server 2025

  • Windows Server 2025 (Server Core installation)

Remediation

Install KB5126651. Install KB5126655. Install KB5126646.

Vendor-listed fixes

  • 10.0.17763.9376

  • 10.0.20348.5761

  • 10.0.26100.33650

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.