CVE-2026-50324: Microsoft AD FS infinite loop denial of service

CVE-2026-50324 · Severity: medium · CVSS 5.9 · Published 2026-07-14

Microsoft Active Directory Federation Services (AD FS), a tool used to provide single sign-on access to applications, is vulnerable to a denial-of-service attack. An unauthorized attacker can remotely trigger a software loop that never ends, causing the service to become unresponsive. This could prevent legitimate users from logging into corporate applications and services, disrupting business operations.

Technologies: Microsoft Active Directory Federation Services, Microsoft Windows Server 2012 R2, Microsoft Windows 10, Microsoft Windows Server 2016, Microsoft Windows Server 2019, Microsoft Windows Server 2022, Microsoft Windows Server 2025. Vendors: Microsoft.

Quick answers

Is CVE-2026-50324 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-50324 being exploited in the wild.
How severe is CVE-2026-50324?
Medium severity, with a CVSS score of 5.9, published 14 July 2026.
Which products and versions are affected?
Microsoft Windows Server 2012 R2 6.3.9600.0 to 6.3.9600.23291; Microsoft Windows 10 10.0.14393.0 to 10.0.14393.9339; Microsoft Windows Server 2016 10.0.14393.0 to 10.0.14393.9339; Microsoft Windows Server 2019 10.0.17763.0 to 10.0.17763.9020; and 1 more.
Is there a fix for CVE-2026-50324?
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-2026-50324 attacked?
It is attacked over the network, in an operating system.
Am I affected by CVE-2026-50324?
Check whether you run Microsoft Active Directory Federation Services, Microsoft Windows Server 2012 R2, 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

A denial-of-service vulnerability exists in Microsoft Active Directory Federation Services (AD FS) due to a loop with an unreachable exit condition (CWE-835). An unauthenticated attacker can exploit this over the network by sending specially crafted requests that trigger an infinite loop within the AD FS process. While the attack complexity is rated as high, a successful exploit results in a complete loss of availability for the federation service. Microsoft has released security updates for various versions of Windows and Windows Server to address this issue.

Affected products

  • Microsoft Windows 10 Version 1607 10.0.14393.0 to 10.0.14393.9339
  • Microsoft Windows 10 Version 1809 10.0.17763.0 to 10.0.17763.9020
  • Microsoft Windows Server 2012 R2 6.3.9600.0 to 6.3.9600.23291
  • Microsoft Windows Server 2016 10.0.14393.0 to 10.0.14393.9339
  • Microsoft Windows Server 2019 10.0.17763.0 to 10.0.17763.9020
  • Microsoft Windows Server 2022 10.0.20348.0 to 10.0.20348.5386
  • Microsoft Windows Server 2025
  • Microsoft Active Directory Federation Services (AD FS)

Timeline

  • 2026-07-14: disclosed
  • 2026-07-14: advisory

References

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