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PatchSiren cyber security CVE debrief

CVE-2026-26177 Microsoft CVE debrief

The Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability, tracked as CVE-2026-26177, is a high-severity vulnerability that allows an authorized attacker to elevate privileges locally. This vulnerability is particularly concerning for defenders responsible for Windows systems, especially those managing Windows 10, Windows 11, and Windows Server environments. The vulnerability's high severity rating of HIGH and CVSS score of 7 necessitate immediate attention. Defenders should prioritize verifying exposure and applying patches to prevent potential local privilege escalation. The CVE record, published on 2026-04-14T16:58:02.355Z, has not been modified, and

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
HIGH 7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-14
Original CVE updated
2026-10-15
Advisory published
2026-04-14
Advisory updated
2026-10-15

Who should care

Defenders responsible for Windows systems, particularly those managing Windows 10, Windows 11, and Windows Server environments, should assess exposure and apply patches.

Why it matters

CVE-2026-26177 is a high-severity elevation of privilege vulnerability in Windows Ancillary Function Driver for WinSock. Defenders should prioritize verifying exposure and applying patches to prevent potential local privilege escalation.

  • Verify exposure of Windows systems to CVE-2026-26177
  • Apply patches from Microsoft for affected Windows versions
  • Monitor systems for potential elevation of privilege attempts

Technical summary

CVE-2026-26177 is an elevation of privilege vulnerability in Windows Ancillary Function Driver for WinSock. An authorized attacker can exploit this vulnerability locally to elevate privileges. The vulnerability has a CVSS score of 7 and a severity rating of HIGH. Defenders should prioritize verifying exposure and applying patches for Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability. The vulnerability's technical details are limited to the CVE Program record and NVD vulnerability detail.

Defensive priority

Defenders should prioritize verifying exposure and applying patches for Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability.

Recommended defensive actions

  • Verify exposure of Windows systems to CVE-2026-26177
  • Apply patches from Microsoft for affected Windows versions
  • Monitor systems for potential elevation of privilege attempts

Evidence notes

The CVE Program record and NVD vulnerability detail provide information on the vulnerability. Microsoft's official advisory is referenced. The vulnerability is confirmed to exist in Windows Ancillary Function Driver for WinSock, and defenders should verify exposure and apply patches. The evidence is limited to the CVE Program record, NVD vulnerability detail, and Microsoft's official advisory. Further verification is required to confirm affected scope and severity.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-26177 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-26177

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

  • CVE-2026-26177 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-26177

    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.