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PatchSiren cyber security CVE debrief

CVE-2011-2005 Microsoft CVE debrief

CVE-2011-2005 is a Microsoft Ancillary Function Driver (afd.sys) vulnerability described as improper input validation and included in CISA’s Known Exploited Vulnerabilities catalog. For defenders, the key takeaway is that CISA has identified this issue as actively exploited enough to require prompt remediation. The supplied source corpus does not include deeper technical detail, so the safest response is to prioritize vendor-guided patching and verify that affected Windows systems are updated.

Vendor
Microsoft
Product
Ancillary Function Driver (afd.sys)
CVSS
Unknown
CISA KEV
Listed
Original CVE published
2022-03-28
Original CVE updated
2022-03-28
Advisory published
2022-03-28
Advisory updated
2022-03-28

Who should care

Windows administrators, endpoint and vulnerability management teams, security operations, and anyone responsible for patching Microsoft-hosted systems should care most. Because afd.sys is a core Windows driver component, exposure may affect broad fleets rather than a narrow application subset. Organizations that track CISA KEV items as a compliance or risk signal should treat this as a high-priority remediation item.

Technical summary

The available source data identifies the issue as an improper input validation vulnerability in Microsoft Ancillary Function Driver (afd.sys). CISA listed CVE-2011-2005 in the KEV catalog on 2022-03-28 and set a remediation due date of 2022-04-18, with the catalog guidance stating: apply updates per vendor instructions. No additional technical details, impact scope, or exploitation mechanics are present in the supplied corpus, so any further claims would be unsupported.

Defensive priority

High. CISA KEV inclusion indicates verified exploitation risk and makes this a priority for patching and exposure review. Use the KEV due date as a strong urgency signal for internal SLAs, especially on internet-facing, privileged, or broadly deployed Windows assets.

Recommended defensive actions

  • Identify all Windows systems that include or depend on Microsoft Ancillary Function Driver (afd.sys).
  • Confirm whether the vendor update guidance for CVE-2011-2005 has been applied across all supported assets.
  • Prioritize remediation before or as soon as possible after the CISA KEV due date of 2022-04-18 for any remaining exposed systems.
  • Validate patch status in vulnerability management and endpoint compliance tools rather than relying on deployment intent alone.
  • Escalate any unpatched systems to incident response or risk owners if remediation cannot be completed quickly.

Evidence notes

This debrief is based only on the supplied CISA KEV source item and its metadata, plus the linked official references in the corpus. The corpus confirms the vendor, product, vulnerability name, KEV status, date added (2022-03-28), due date (2022-04-18), and the vendor-action note to apply updates per vendor instructions. It does not provide exploit details, affected versions, or impact specifics, so those are intentionally not asserted here. The dates in this debrief refer to KEV/source publication context, not the original vulnerability disclosure date.

Official resources

CISA added CVE-2011-2005 to the Known Exploited Vulnerabilities catalog on 2022-03-28 and set a due date of 2022-04-18. The supplied corpus does not include the original vulnerability disclosure date.