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CVE-2026-33100

Windows - Ancillary Function Driver for WinSock

Microsoft CVSS 7 Updated April 16, 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 on a Windows system, which could be used to install malware, steal sensitive data, or disrupt system operations."

Anticipated Attack Path

  1. 1. Initial Exploitation: An attacker gains access to a Windows system with the vulnerable Ancillary Function Driver for WinSock
  2. 2. Privilege Escalation: The attacker exploits the use-after-free vulnerability to elevate their privileges
  3. 3. Post-Exploitation: The attacker uses their elevated privileges to install malware, steal sensitive data, or disrupt system operations

Am I Vulnerable?

  • Verify the presence of the Ancillary Function Driver for WinSock on Windows systems
  • Check for any suspicious activity related to the Ancillary Function Driver for WinSock
  • Apply the latest security patches from Microsoft to remediate the vulnerability

Operational Audit Arsenal

Target Type Driver
Target Asset afd.sys
Standard Path C:\Windows\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

Minimal to Moderate

Internal Work Notes

CVE-2026-33100: Use-after-free vulnerability in Windows Ancillary Function Driver for WinSock allows privilege escalation. Apply latest Microsoft security patches to remediate.

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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.