# CVE-2026-54983: Microsoft AD FS stack-based buffer overflow denial of service

Source: https://junglewise.ai/threats/cve-2026-54983-microsoft-ad-fs-stack-based-buffer-overflow-denial-of-service  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-14. Updated: 2026-07-14  
License: CC BY 4.0 with a link back

CVE-2026-54983 · 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 over the network. AD FS is a critical component used to manage single sign-on and identity access across different applications. If exploited, this could prevent users from logging into corporate systems, causing a significant disruption to business operations.

Technologies: [Microsoft Active Directory Federation Services](https://junglewise.ai/threats/technologies/active-directory-federation-services), [Microsoft Windows 11](https://junglewise.ai/threats/technologies/windows-11), [Microsoft Windows 10](https://junglewise.ai/threats/technologies/windows-10), [Microsoft Windows Server 2012](https://junglewise.ai/threats/technologies/windows-server-2012). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-54983 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-54983 being exploited in the wild.

**How severe is CVE-2026-54983?** 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 on affected Windows platforms; Microsoft Windows 11 24H2, 25H2, 26H1; Microsoft Windows 10 1607, 1809, 21H2, 22H2; Microsoft Windows Server 2012 All versions.

**Is there a fix for CVE-2026-54983?** 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-2026-54983 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-2026-54983?** 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

A stack-based buffer overflow (CWE-121) exists in Microsoft Active Directory Federation Services (AD FS). The vulnerability can be triggered by a remote, unauthenticated attacker over the network without any user interaction. Successful exploitation results in a denial-of-service (DoS) condition, crashing the AD FS service and preventing identity federation and authentication processes. Microsoft has released security updates to address this issue across multiple versions of Windows and Windows Server.

## Affected products

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

## Timeline

- 2026-07-14: disclosed
- 2026-07-14: advisory: Microsoft released security update guide for CVE-2026-54983

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-54983](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-54983)

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