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PatchSiren cyber security CVE debrief

CVE-2026-77494 Microsoft CVE debrief

A type confusion vulnerability in Windows DHCP Server could allow an unauthorized attacker to deny service over a network. The vulnerability has a CVSS score of 7.5 and is considered HIGH severity. Microsoft has released a patch for this vulnerability. System administrators and security teams should assess exposure and apply patches immediately to prevent potential denial of service attacks. The vulnerability affects Windows DHCP Server installations, and its exploitation could lead to network disruptions. It is essential to verify affected versions and patching status, as well as monitor network traffic for potential exploitation attempts.

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
2026-09-16
Advisory published
2026-09-08
Advisory updated
2026-09-16

Who should care

System administrators and security teams responsible for managing Windows DHCP Server installations should assess exposure and apply patches immediately to prevent potential denial of service attacks.

Why it matters

A type confusion vulnerability in Windows DHCP Server could allow an unauthorized attacker to deny service over a network. System administrators and security teams should assess exposure and apply patches immediately to prevent potential denial of service attacks.

  • Potential denial of service attacks over a network
  • Requires verification of affected versions and patching status
  • Necessitates monitoring network traffic for potential exploitation attempts
  • Prioritization of patching based on CVSS score and severity

Technical summary

The vulnerability is a type confusion issue in Windows DHCP Server, which could allow an unauthorized attacker to deny service over a network. The CVSS vector is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. This type of vulnerability occurs when the server incorrectly handles data, leading to potential crashes or unexpected behavior. To mitigate this vulnerability, it is crucial to apply patches immediately and review vulnerability management processes to ensure timely patching of critical vulnerabilities.

Defensive priority

Apply patches immediately to prevent potential denial of service attacks

Recommended defensive actions

  • Apply patches immediately to prevent potential denial of service attacks
  • Review and update vulnerability management processes to ensure timely patching of critical vulnerabilities
  • Monitor network traffic for potential exploitation attempts

Evidence notes

The vulnerability is described as a type confusion issue in Windows DHCP Server, which could allow an attacker to deny service over a network. The CVSS vector is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-77494 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-77494

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

  • CVE-2026-77494 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-77494

    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.