CVE-2006-3440: Microsoft Windows Winsock API buffer overflow allows remote code execution

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 19 September 2026. Confidence: medium.

critical priorityCVSS 2.0 base score is 10.0 with network-reachable, unauthenticated, complete-impact exploitation, and EPSS is at the 99th percentile, so the flaw warrants top remediation priority despite the lack of KEV listing.

What it is

A buffer overflow exists in the Winsock API on Windows 2000 SP4, XP SP1/SP2, and Server 2003 SP1, reachable by remote attackers through unspecified vectors. The flaw is rated 10.0 under CVSS 2.0 for complete confidentiality, integrity, and availability impact, so successful exploitation could fully compromise the host. The description does not identify the exact Winsock function or trigger, which limits precise reproduction guidance.

Impact

An unauthenticated remote attacker can execute arbitrary code with the privileges of the affected service or process, potentially gaining full control of the system. Because the vector is network-reachable with no authentication, exposure is broad wherever the affected Windows versions are internet- or network-facing.

Attack surface

The vulnerability is network-reachable (AV:N) with low complexity and no authentication required (AC:L/Au:N), but the description does not specify which Winsock operation or protocol path triggers the overflow. No user interaction is indicated by the vector.

Exploitation

CVE-2006-3440 is not listed in CISA KEV and no ransomware groups are documented using it, but EPSS shows a 30-day probability of 0.573 (99th percentile), indicating high predicted exploitation likelihood. Reference tags include Patch and US Government Resource, and no public exploit references are tagged in the record.

What to do

• Apply the Microsoft security update for MS06-041 (the vendor bulletin referenced in the record) to all affected Windows 2000 SP4, XP SP1/SP2, and Server 2003 SP1 systems.
• Retire or isolate unsupported Windows 2000 and XP SP1/SP2 hosts that cannot receive the patch, since these platforms are long past end of support.
• Restrict network exposure of affected hosts with host and perimeter firewalls, allowing only required services and protocols.
• Monitor vendor and CERT/CC advisories for updated guidance, as the record does not specify the exact Winsock trigger.
• Where feasible, apply the OVAL definition referenced in the record to verify patch state across the estate.

Detection

• Hunt for unexpected crashes or restarts of processes that use Winsock on affected Windows versions, which may indicate exploitation attempts.
• Monitor network traffic to and from affected hosts for anomalous or malformed Winsock-related requests, though the record does not identify a specific signature.
• Correlate host logs for suspicious child processes or code execution originating from network-facing services on Windows 2000, XP, and Server 2003.
• Track patch compliance for MS06-041 across the affected product list and flag unpatched hosts for remediation.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.