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CVE-2026-88102 Microsoft CVE debrief

Microsoft Failover Cluster Remote Code Execution Vulnerability allows unauthorized attackers to execute code over a network due to a use-after-free issue in Windows Failover Cluster. The vulnerability has a CVSS score of 9.8 and is considered CRITICAL. This vulnerability affects Windows Server 2019, 2022, and 2025 systems, particularly those using Windows Failover Cluster. Defenders should assess exposure and prioritize patching or mitigation. The vulnerability allows remote code execution without user interaction, emphasizing the need for immediate patching or mitigation, network segmentation, and monitoring to limit exposure and detect potential attacks. Verification of system A

Vendor
Microsoft
Product
Windows Server 2019
CVSS
CRITICAL 9.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-10-13
Original CVE updated
2026-10-14
Advisory published
2026-10-13
Advisory updated
2026-10-14

Who should care

Defenders responsible for Windows Server 2019, 2022, and 2025 systems, especially those using Windows Failover Cluster, should assess exposure and prioritize patching or mitigation.

Why it matters

CVE-2026-88102 is a CRITICAL vulnerability in Windows Failover Cluster allowing remote code execution. Defenders should prioritize patching and implement network segmentation and monitoring to limit exposure and detect potential attacks.

  • Remote code execution is possible without user interaction.
  • Immediate patching or mitigation is required to prevent exploitation.
  • Network segmentation and monitoring are necessary to limit and detect potential attacks.
  • Verification of system configurations and inventory checks are essential to ensure exposure assessment.

Technical summary

The vulnerability is a use-after-free issue in Windows Failover Cluster, which allows an unauthorized attacker to execute code over a network. The CVSS score is 9.8, indicating a CRITICAL severity level. Affected products include Windows Server 2019, 2022, and 2025, with specific versions being vulnerable.

Defensive priority

Defenders should prioritize patching or mitigating this vulnerability, especially for Windows Server 2019, 2022, and 2025 systems, as it allows for remote code execution.

Recommended defensive actions

  • Apply patches or updates provided by Microsoft for the affected Windows Server versions.
  • Implement network segmentation to limit access to vulnerable systems.
  • Monitor network traffic for suspicious activity related to Windows Failover Cluster.
  • Verify and restrict access to Windows Failover Cluster services from untrusted networks.

Evidence notes

The vulnerability is described as a use-after-free issue in Windows Failover Cluster, allowing remote code execution. Affected products include Windows Server 2019, 2022, and 2025, with specific versions being vulnerable.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-88102 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-88102

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

  • CVE-2026-88102 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-88102

    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.