CVE-2011-2005: in the CISA KEV catalogue
Microsoft Ancillary Function Driver (afd.sys) Improper Input Validation Vulnerability. CISA added CVE-2011-2005 to the Known Exploited Vulnerabilities catalogue on 2022-03-28 with a default due date of 2022-04-18. Known ransomware campaign use: Unknown. Forensic triage flag: No.
afd.sys in the Ancillary Function Driver in Microsoft Windows does not properly validate user-mode input passed to kernel mode, which allows local users to gain privileges via a crafted application. (CISA description)
- Vendor / product
- Microsoft Ancillary Function Driver (afd.sys)
- CWE
- CWE-264
- CISA required action
- Apply updates per vendor instructions.
- EPSS
- 32%, percentile 98 (scored 2026-11-04)
EPSS puts about 32 in 100 odds (32%) on exploitation activity being observed in the next 30 days. Its score is higher than or equal to that of 98% of scored CVEs. This is a model estimate about exploitation anywhere, not about your environment.
Vendor and reference links (from CISA)
Your own deadline under CISA BOD 26-04 depends on exposure, automatability and technical impact: work it out with the BOD 26-04 calculator.
Frequently asked questions
Is CVE-2011-2005 in the CISA KEV catalogue?
Yes. CISA added CVE-2011-2005 (Microsoft Ancillary Function Driver (afd.sys) Improper Input Validation Vulnerability) to the Known Exploited Vulnerabilities catalogue on 2022-03-28. CISA's default due date for it is 2022-04-18.
Is CVE-2011-2005 used in ransomware attacks?
CISA marks known ransomware campaign use as Unknown for CVE-2011-2005. That means CISA lacks confirmation, not that ransomware groups do not use it.
What should I do about CVE-2011-2005?
CISA's required action: Apply updates per vendor instructions.
Sources
- CISA, Known Exploited Vulnerabilities Catalog (accessed 2026-11-03)
- FIRST, Exploit Prediction Scoring System (EPSS) (EPSS by FIRST; scores generated by Empirical Security)
- NVD record for CVE-2011-2005