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PatchSiren cyber security CVE debrief

CVE-2026-78446 Microsoft CVE debrief

A use-after-free vulnerability in Windows Distributed File System (DFS) allows an authorized attacker to deny service over a network. This CVE was published on 2026-09-08T18:20:42.417Z and was last modified on 2026-09-11T18:59:47.347Z. The vulnerability is a Medium-severity issue with a CVSS score of 5.3. Windows administrators and security teams should assess exposure, prioritize patching, and verify compensating controls for Windows DFS deployments. The CVE record and NVD detail page provide information on the vulnerability, including its description, CVSS score, and affected products.

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-08
Original CVE updated
2026-10-14
Advisory published
2026-09-08
Advisory updated
2026-10-14

Who should care

Windows administrators and security teams responsible for managing Windows DFS deployments should assess exposure and prioritize patching for this vulnerability.

Why it matters

CVE-2026-78446 is a Medium-severity vulnerability in Windows Distributed File System (DFS) that allows an authorized attacker to deny service over a network. Windows administrators and security teams should assess exposure, prioritize patching, and verify compensating controls for Windows DFS deployments.

  • Service denial over a network for authorized attackers.
  • Potential disruption to Windows DFS services.
  • Requires verification of affected versions and exposure.
  • Patching priority for Windows DFS deployments.

Technical summary

The vulnerability is a use-after-free issue in Windows Distributed File System (DFS), which allows an authorized attacker to deny service over a network. The CVSS score for this vulnerability is 5.3, and the severity is Medium. Affected products include various versions of Windows 10, Windows 11, and Windows Server.

Defensive priority

Medium-priority patching and verification recommended for Windows DFS deployments.

Recommended defensive actions

  • Apply patches from Microsoft for affected Windows versions.
  • Verify and apply compensating controls for Windows DFS deployments.
  • Monitor Windows DFS systems for potential service denial.

Evidence notes

The CVE record and NVD detail page provide information on the vulnerability, including its description, CVSS score, and affected products. Microsoft has provided a patch and vendor advisory for this vulnerability.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-78446 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-78446

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

  • CVE-2026-78446 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-78446

    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.