CVE-2011-2005: Microsoft Ancillary Function Driver (afd.sys) Improper Input Validation Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 28 Mar 2022, 3,820 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 31.8%
EPSS score, percentile 98.3 of all scored records
- How severe?
- 7.8 High
CVSS v3.1 base score, from CISA's enrichment of the record
- What should I do?
CISA deadline 18 Apr 2022. Apply updates per vendor instructions.
- Which versions are affected?
Not stated. The CVE record gives vendor and product as “n/a” and the version as “unspecified”.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
What to do
Required action, set by CISA
Apply updates per vendor instructions.
CISA due date for this action: 18 April 2022.
Advisories and patches
Linked from CISA's catalog entry
Affected products and versions
The CVE record does not name affected products or versions: vendor and product are “n/a” and the version is “unspecified”.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
About this vulnerability
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.
Summary: CISA's KEV catalog, as of 28 Oct 2026.
- CISA added CVE-2011-2005 to its Known Exploited Vulnerabilities (KEV) catalog on 28 Mar 2022.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 18 Apr 2022.
- The CVE record was published on 12 Oct 2011, 3,820 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 7.8 (High), taken from CISA's enrichment of the record.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 31.8% (percentile 98.3), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.
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: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
Weakness
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| 12 Oct 2011 | CVE record published |
| 28 Mar 2022 | Added to CISA KEV |
| 18 Apr 2022 | CISA due date for the required action |
| 22 Oct 2025 | CVE record last updated |
References
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