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CVE-2026-21241

Windows - Ancillary Function Driver for WinSock

Microsoft CVSS 7 Updated March 15, 2026

Executive Risk Summary

"A use-after-free vulnerability in the Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally, potentially leading to unauthorized access to sensitive data and system resources. This vulnerability can be exploited to gain elevated privileges, which could be used to compromise the entire system."

Operational Audit Arsenal

Target Type Driver
Target Asset afd.sys
Standard Path %windir%\System32\drivers
PowerShell
# 🛠️ Senior Engineer Universal Audit
# Target: afd.sys (Driver)
$Targets = 'afd.sys'
$SearchPaths = @("$env:windir\System32", "$env:ProgramFiles", "${env:ProgramFiles(x86)}")

Get-ChildItem -Path $SearchPaths -Include $Targets -Recurse -ErrorAction SilentlyContinue | 
Select-Object FullName, @{Name="Version";Expression={$_.VersionInfo.ProductVersion}}

Patch Impact Forecast

Reboot Required Likely

Network services may be affected

Internal Work Notes

CVE-2026-21241: Local privilege escalation vulnerability in Windows Ancillary Function Driver for WinSock, requiring patching and reboot to mitigate

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Intelligence Sources

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Data compiled from NVD, MSRC, and CISA KEV Catalog. Intelligence synthesized via AI. Scripts provided for diagnostic purposes under MIT License.