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CVE-2026-78464 Microsoft CVE debrief

A time-of-check time-of-use (toctou) race condition vulnerability exists in the Windows MIDI Service Module, which could allow an authorized attacker to elevate privileges locally. This CVE was published on 2026-09-08T17:18:30.613Z and was last modified on 2026-10-08T18:19:35.121Z. The vulnerability affects Windows 11 Version 24H2, Windows 11 Version 25H2, and Windows 11 version 26H1 systems. Defenders should assess exposure and apply patches from Microsoft to prevent potential privilege elevation. The CVE Program record and NVD vulnerability detail provide information on the vulnerability.

Vendor
Microsoft
Product
Windows 11 Version 24H2
CVSS
HIGH 7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-08
Original CVE updated
2026-10-08
Advisory published
2026-09-08
Advisory updated
2026-10-08

Who should care

Defenders responsible for Windows 11 Version 24H2, Windows 11 Version 25H2, and Windows 11 version 26H1 systems should assess exposure to this vulnerability and apply patches from Microsoft.

Why it matters

Defenders should prioritize verifying exposure of Windows 11 Version 24H2, Windows 11 Version 25H2, and Windows 11 version 26H1 systems to this vulnerability and applying patches from Microsoft to prevent potential privilege elevation.

  • Potential privilege elevation on affected systems
  • Need to verify exposure and apply patches
  • Possible impact on system security if not mitigated

Technical summary

A time-of-check time-of-use (toctou) race condition vulnerability exists in the Windows MIDI Service Module. An authorized attacker could exploit this vulnerability to elevate privileges locally. The vulnerability is related to the Windows MIDI Service Module and affects Windows 11 Version 24H2, Windows 11 Version 25H2, and Windows 11 version 26H1 systems. Defenders should prioritize verifying exposure and applying patches from Microsoft.

Defensive priority

Defenders should prioritize verifying exposure of Windows 11 Version 24H2, Windows 11 Version 25H2, and Windows 11 version 26H1 systems to this vulnerability and applying patches from Microsoft.

Recommended defensive actions

  • Verify exposure of Windows 11 Version 24H2, Windows 11 Version 25H2, and Windows 11 version 26H1 systems to this vulnerability
  • Apply patches from Microsoft for the affected systems
  • Monitor systems for potential privilege elevation attempts

Evidence notes

The CVE Program record and NVD vulnerability detail provide information on the vulnerability. Microsoft has also provided a vendor advisory and patch for the vulnerability.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-78464 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-78464

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

  • CVE-2026-78464 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-78464

    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.