Vulnerability record

CVE-2011-2005

Microsoft Ancillary Function Driver (afd.sys) Improper Input Validation Vulnerability

HighExploitation confirmedCISA KEV

What should I do?

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog: attackers are using it. If you run Ancillary Function Driver (afd.sys), fix it now.

CISA required action: Apply updates per vendor instructions.

US federal civilian agencies must remediate by Apr 18, 2022.

Patch status

Official fix available since Sep 30, 2026

Apply the vendor's update to every affected system. Check the fixed-in versions below where known.

Basis: NVD patch reference

Patch or advisory on docs.microsoft.com (opens in a new tab)

Description

afd.sys in the Ancillary Function Driver in Microsoft Windows XP SP2 and SP3 and Server 2003 SP2 does not properly validate user-mode input passed to kernel mode, which allows local users to gain privileges via a crafted application, aka "Ancillary Function Driver Elevation of Privilege Vulnerability."

Source: NIST National Vulnerability Database. Official vulnerability data, reproduced as published.

Affected products

Products affected by this vulnerability, with versions and the source of each entry
Product	Vendor	Source
Ancillary Function Driver (afd.sys)	Microsoft	KEV

Sources: KEV = CISA Known Exploited Vulnerabilities catalog. Version details have not been published yet.

Intelligence timeline

Developments from the last 30 days, newest first.

CVSS scoredUpdateKEVSep 30, 2026
CVE-2011-2005 scored CVSS 7.8: Microsoft Ancillary Function Driver (afd.sys), Microsoft Ancillary Function Driver (afd.sys) Improper Input Validation Vulnerability
CISA lists this as exploited in the wild. Unpatched Ancillary Function Driver (afd.sys) systems are exposed to active attacks now.
Basis: NIST National Vulnerability Database
Patch releasedUpdateKEVSep 30, 2026
Patch released for CVE-2011-2005: Microsoft Ancillary Function Driver (afd.sys), Microsoft Ancillary Function Driver (afd.sys) Improper Input Validation Vulnerability
An official fix is now available for Microsoft Ancillary Function Driver (afd.sys). This vulnerability is being exploited, so apply it promptly.
Basis: NVD patch reference

1 earlier event is available with a subscription. See plans.

Coverage

We have not published a story about this vulnerability yet.

References

nvd.nist.gov https://nvd.nist.gov/vuln/detail/CVE-2011-2005
docs.microsoft.com https://docs.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-080
oval.cisecurity.org https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A13114
cisa.gov https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2011-2005