CVE-2026-50647: Microsoft AD FS denial of service via infinite loop

CVE-2026-50647 · Severity: high · CVSS 7.5 · Published 2026-07-14

A vulnerability in Microsoft's Active Directory Federation Services (AD FS) allows an unauthorized person to crash the service remotely. AD FS is a critical component used to manage single sign-on and user authentication across different applications. If exploited, this could prevent legitimate users from logging into corporate systems, causing a significant disruption to business operations.

Technologies: Microsoft Active Directory Federation Services, Microsoft Windows 11, Microsoft Windows 10, Microsoft Windows Server 2012. Vendors: Microsoft.

Quick answers

Is CVE-2026-50647 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-50647 being exploited in the wild.
How severe is CVE-2026-50647?
High severity, with a CVSS score of 7.5, published 14 July 2026.
Which products and versions are affected?
Microsoft Active Directory Federation Services All versions running on affected Windows OS; Microsoft Windows 11 Multiple versions affected; Microsoft Windows 10 Multiple versions affected; Microsoft Windows Server 2012 Multiple versions affected.
Is there a fix for CVE-2026-50647?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-50647 attacked?
It is attacked over the network, in an operating system.
Am I affected by CVE-2026-50647?
Check whether you run Microsoft Active Directory Federation Services, Microsoft Windows 11, Microsoft Windows 10 or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

This vulnerability is classified as an infinite loop (CWE-835) within Active Directory Federation Services (AD FS). An unauthenticated attacker can trigger this condition by sending a specially crafted request over the network, causing the service to enter a loop with an unreachable exit condition. This results in high CPU utilization and service unavailability (Denial of Service). The vulnerability affects multiple versions of Windows and Windows Server. Microsoft has released security updates to address this issue; administrators should apply the relevant OS patches to remediate the flaw.

Affected products

  • Microsoft Windows 10 Version 1607, 1809, 21H2, 22H2 Multiple versions affected
  • Microsoft Windows 11 Version 24H2, 25H2, 26H1 Multiple versions affected
  • Microsoft Windows Server 2012 Multiple versions affected
  • Microsoft Active Directory Federation Services (AD FS) All versions running on affected Windows OS

Timeline

  • 2026-07-14: disclosed: Initial publication of CVE-2026-50647 by Microsoft
  • 2026-07-14: advisory: NVD entry created

References

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