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CVE-2026-77904 Microsoft CVE debrief

CVE-2026-77904 is a high-severity vulnerability in the Windows Volume Manager Extension Driver that allows an authorized attacker to elevate privileges locally. The vulnerability has a CVSS score of 7.8 and is classified as HIGH. Microsoft has released a patch for this vulnerability, and defenders should prioritize patching systems that are exposed to this vulnerability.

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
HIGH 7.8
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

Defenders who are responsible for patching and securing Windows systems should prioritize patching systems that are exposed to this vulnerability.

Why it matters

CVE-2026-77904 is a high-severity vulnerability that allows an authorized attacker to elevate privileges locally, which could lead to lateral movement within a network. Defenders should prioritize patching systems that are exposed to this vulnerability.

  • Elevation of privileges by an authorized attacker
  • Potential for lateral movement within a network
  • Need for patching and verification of systems

Technical summary

The vulnerability is a heap-based buffer overflow in the Windows Volume Manager Extension Driver that allows an authorized attacker to elevate privileges locally. The vulnerability affects multiple versions of Windows, including Windows 10, Windows 11, and Windows Server.

Defensive priority

Patching systems that are exposed to this vulnerability is a high priority.

Recommended defensive actions

  • Patch systems that are exposed to this vulnerability
  • Verify that systems are patched or mitigated
  • Monitor systems for potential exploitation attempts

Evidence notes

The CVE record and NVD vulnerability detail provide information on the vulnerability, including its CVSS score and affected systems. The vulnerability affects multiple versions of Windows, including Windows 10, Windows 11, and Windows Server. There is no information on exploitation or publicly available exploits. Defenders should verify patch deployment and system exposure, review official advisories for affected scope and severity, and monitor for potential exploitation attempts.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-77904 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-77904

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

  • CVE-2026-77904 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-77904

    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.