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CVE-2026-71338 Microsoft CVE debrief

A double free vulnerability in Windows Failover Cluster allows an authorized attacker to elevate privileges locally. This CVE was published on 2026-09-08T18:20:13.573Z and was last modified on 2026-09-15T13:07:56.120Z. The vulnerability is a double free in Windows Failover Cluster, which could allow an authorized attacker to elevate privileges locally. The CVSS score is 6.4, indicating a medium severity. The vulnerability affects multiple versions of Windows, including Windows 10, Windows Server 2012, Windows Server 2016, Windows Server 2019, Windows Server 2022, and Windows Server 2025. Defenders responsible for Windows Failover Cluster systems, especially those with high should

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
MEDIUM 6.4
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-08
Original CVE updated
2026-09-15
Advisory published
2026-09-08
Advisory updated
2026-09-15

Who should care

Defenders responsible for Windows Failover Cluster systems, especially those with high privilege requirements, should prioritize patching this vulnerability.

Why it matters

Defenders should prioritize patching this vulnerability, especially for systems with high privilege requirements, as it could allow an authorized attacker to elevate privileges locally.

  • Potential privilege escalation
  • Possible system compromise if exploited

Technical summary

The vulnerability is a double free in Windows Failover Cluster, which could allow an authorized attacker to elevate privileges locally. The CVSS score is 6.4, indicating a medium severity. The vulnerability affects multiple versions of Windows, including Windows 10, Windows Server 2012, Windows Server 2016, Windows Server 2019, Windows Server 2022, and Windows Server 2025.

Defensive priority

Defenders should prioritize patching this vulnerability, especially for systems with high privilege requirements.

Recommended defensive actions

  • Patch vulnerable systems, especially those with high privilege requirements
  • Verify and apply the vendor's advisory
  • Monitor for potential exploitation attempts

Evidence notes

The vulnerability is described as a double free in Windows Failover Cluster, which could allow an authorized attacker to elevate privileges locally. The CVSS score is 6.4, indicating a medium severity.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-71338 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-71338

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

  • CVE-2026-71338 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-71338

    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.