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PatchSiren cyber security CVE debrief

CVE-2026-78445 Microsoft CVE debrief

A critical vulnerability exists in the Windows Services for NFS ONCRPC XDR Driver, allowing an unauthorized attacker to execute code over a network. This use-after-free vulnerability has a CVSS score of 9.8 and is considered critical. The vulnerability affects Windows Server infrastructure, and administrators must assess exposure and apply patches immediately to prevent potential code execution and data breaches. The issue is caused by a use-after-free error in the Windows Services for NFS ONCRPC XDR Driver.

Vendor
Microsoft
Product
Windows Server 2012
CVSS
CRITICAL 9.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-08
Original CVE updated
2026-09-11
Advisory published
2026-09-08
Advisory updated
2026-09-11

Who should care

Administrators responsible for Windows Server infrastructure should assess exposure and apply patches immediately. This includes reviewing and updating inventory to ensure all affected systems are identified and patched, and monitoring for any suspicious activity related to this vulnerability. Failure to patch vulnerable systems could lead to system compromise and data breaches.

Why it matters

CVE-2026-78445 is a critical vulnerability in the Windows Services for NFS ONCRPC XDR Driver that allows unauthorized code execution over a network. Administrators must assess exposure, apply patches, and monitor systems to prevent exploitation and potential data breaches.

  • Potential code execution over a network requires immediate patching and verification of vulnerable systems.
  • Unauthorized access could lead to system compromise and data breaches.
  • Successful exploitation could result in lateral movement within the network.
  • Verification of patch application and system monitoring are crucial to prevent exploitation.

Technical summary

The vulnerability exists in the Windows Services for NFS ONCRPC XDR Driver and allows an unauthorized attacker to execute code over a network. The issue is caused by a use-after-free error. This vulnerability has a CVSS score of 9.8 and is considered critical. Administrators responsible for Windows Server infrastructure should assess exposure and apply patches immediately.

Defensive priority

Immediate attention is required to patch vulnerable systems, particularly for administrators responsible for Windows Server infrastructure.

Recommended defensive actions

  • Apply the patch provided by Microsoft to vulnerable Windows Server systems.
  • Review and update inventory to ensure all affected systems are identified and patched.
  • Monitor for any suspicious activity related to this vulnerability.

Evidence notes

The vulnerability is described as a use-after-free issue in the Windows Services for NFS ONCRPC XDR Driver. Microsoft has provided a patch for this vulnerability, and the NVD has analyzed the CVE.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-78445 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-78445

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

  • CVE-2026-78445 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-78445

    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.