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PatchSiren cyber security CVE debrief

CVE-2026-72978 Microsoft CVE debrief

CVE-2026-72978 is a vulnerability in Active Directory Federation Services (AD FS) that allows an unauthorized attacker to deny service over a network. The vulnerability has a CVSS score of 5.9 and a severity of MEDIUM. Microsoft has released a patch for this vulnerability. Defenders responsible for AD FS systems, particularly those with exposure to untrusted networks, should prioritize patching vulnerable systems and monitoring for potential denial-of-service attacks. The vulnerability is caused by the allocation of resources without limits or throttling in Active Directory Federation Services (AD FS). This allows an unauthorized attacker to deny service over a network.

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
MEDIUM 5.9
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-08
Original CVE updated
2026-09-22
Advisory published
2026-09-08
Advisory updated
2026-09-22

Who should care

Defenders responsible for AD FS systems, particularly those with exposure to untrusted networks, should prioritize patching vulnerable systems and monitoring for potential denial-of-service attacks.

Why it matters

CVE-2026-72978 is a vulnerability in Active Directory Federation Services (AD FS) that allows an unauthorized attacker to deny service over a network. Defenders responsible for AD FS systems should prioritize patching vulnerable systems and monitoring for potential denial-of-service attacks.

  • Denial of service attacks may occur against unpatched AD FS systems.
  • Defenders should verify that AD FS systems are updated with the latest security patches to prevent potential attacks.
  • Patching vulnerable systems is a high priority to prevent potential denial-of-service attacks.

Technical summary

The vulnerability is caused by the allocation of resources without limits or throttling in Active Directory Federation Services (AD FS). This allows an unauthorized attacker to deny service over a network. The vulnerability has a CVSS score of 5.9 and a severity of MEDIUM.

Defensive priority

Defenders should prioritize patching vulnerable systems, particularly those with exposure to untrusted networks.

Recommended defensive actions

  • Patch vulnerable systems, particularly those with exposure to untrusted networks.
  • Verify that AD FS systems are updated with the latest security patches.
  • Monitor AD FS systems for potential denial-of-service attacks.

Evidence notes

The vulnerability is described in the CVE Program record and the NVD vulnerability detail page. Microsoft has released a vendor advisory and patch for this vulnerability.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-72978 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-72978

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-72978 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-72978

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.