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CVE-2026-68820 Microsoft CVE debrief

Microsoft Windows Ancillary Function Driver for WinSock Use-After-Free Vulnerability debrief. The vulnerability is being actively exploited, posing a high risk to affected systems. Defenders should prioritize mitigation to prevent potential system compromise and instability. This vulnerability affects Microsoft Windows systems using the Ancillary Function Driver for WinSock. The vulnerability class is Use-After-Free, which can lead to potential system crashes or instability, possible elevation of privileges, and risk of lateral movement or further exploitation.

Vendor
Microsoft
Product
Windows Ancillary Function Driver for WinSock
CVSS
HIGH 7
CISA KEV
Listed
Original CVE published
2026-08-11
Original CVE updated
2026-08-11
Advisory published
2026-08-11
Advisory updated
2026-08-11

Who should care

Defenders and administrators of Microsoft Windows systems, particularly those using the Ancillary Function Driver for WinSock, should assess exposure and prioritize mitigation.

Why it matters

This vulnerability in Microsoft Windows Ancillary Function Driver for WinSock is being actively exploited, posing a high risk to affected systems. Defenders should prioritize mitigation to prevent potential system compromise and instability.

  • Potential system crashes or instability
  • Possible elevation of privileges
  • Risk of lateral movement or further exploitation

Technical summary

The Microsoft Windows Ancillary Function Driver for WinSock has a Use-After-Free Vulnerability, which is being actively exploited. This vulnerability affects Microsoft Windows systems using the Ancillary Function Driver for WinSock. The vulnerability can lead to potential system crashes or instability, possible elevation of privileges, and risk of lateral movement or further exploitation. Defenders should prioritize mitigation to prevent potential system compromise and instability.

Defensive priority

High priority due to known exploitation

Recommended defensive actions

  • Apply mitigations in accordance with vendor instructions
  • Ensure compliance with CISA's BOD 26-04 guidance
  • Prioritize security updates based on risk

Evidence notes

The CISA Known Exploited Vulnerabilities catalog and CVE Program record confirm the vulnerability's existence and Microsoft's affected status. The vulnerability has been added to the CISA Known Exploited Vulnerabilities catalog on 2026-08-11. The CVE record was published on 2026-08-11T00:00:00.000Z and has not been modified since then. Defenders should verify affected scope, severity, and vendor guidance through official advisory or CVE record review.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-68820 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-68820

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

  • CVE-2026-68820 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-68820

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

  • CISA Known Exploited Vulnerabilities catalog

    Publisher, destination, and source semantics verified

    URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Cybersecurity and Infrastructure Security Agency - Official CISA catalog of vulnerabilities known to be exploited in the wild.

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.