CVE-2009-1926

Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP2, Vista Gold, SP1, and SP2, and Server 2008 Gold and SP2 allow remote attackers to cause a denial of service (TCP outage) via a series of TCP sessions that have pending data and a (1) small or (2) zero receive window size, and remain in the FIN-WAIT-1 or FIN-WAIT-2 state indefinitely, aka "TCP/IP Orphaned Connections Vulnerability."

Published: 2009-09-08 Last update: 2026-04-23 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2009-1926 is rated Moderate Risk (64/100): CVSS High severity, with high exploitation likelihood (EPSS 70.54%, 99th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2009-1926

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-01-28 72.26% 70.54% -1.72%
2 2025-12-28 70.37% 72.26% +1.89%
3 2025-12-27 — 70.37% —

Full EPSS history (25 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2009-1926

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 2.0 HIGH
AV:N/AC:L/Au:N/C:N/I:N/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:C)
Complete availability impact.
 10.0 6.9 [email protected]

Weakness enumeration for CVE-2009-1926

Affected software / configurations for CVE-2009-1926

Vendor Product Version Raw CPE
microsoft windows_2000 — cpe:2.3:o:microsoft:windows_2000:-:sp4:*:*:*:*:*:*
microsoft windows_server_2003 — cpe:2.3:o:microsoft:windows_server_2003:*:sp2:*:*:*:*:*:*
microsoft windows_server_2008 — cpe:2.3:o:microsoft:windows_server_2008:*:*:itanium:*:*:*:*:*
microsoft windows_server_2008 — cpe:2.3:o:microsoft:windows_server_2008:-:-:x32:*:*:*:*:*
microsoft windows_server_2008 — cpe:2.3:o:microsoft:windows_server_2008:-:-:x64:*:*:*:*:*
microsoft windows_server_2008 — cpe:2.3:o:microsoft:windows_server_2008:-:sp2:itanium:*:*:*:*:*
microsoft windows_server_2008 — cpe:2.3:o:microsoft:windows_server_2008:-:sp2:x64:*:*:*:*:*
microsoft windows_server_2008 — cpe:2.3:o:microsoft:windows_server_2008:-:sp2:x86:*:*:*:*:*
microsoft windows_vista — cpe:2.3:o:microsoft:windows_vista:*:*:*:*:*:*:*:*
microsoft windows_vista — cpe:2.3:o:microsoft:windows_vista:*:sp1:*:*:*:*:*:*
microsoft windows_vista — cpe:2.3:o:microsoft:windows_vista:*:sp2:*:*:*:*:*:*
microsoft windows_vista — cpe:2.3:o:microsoft:windows_vista:-:-:x64:*:*:*:*:*
microsoft windows_vista — cpe:2.3:o:microsoft:windows_vista:-:sp1:*:*:*:*:*:*
microsoft windows_vista — cpe:2.3:o:microsoft:windows_vista:-:sp2:*:*:*:*:*:*
microsoft windows_xp — cpe:2.3:o:microsoft:windows_xp:*:sp2:*:*:*:*:*:*
microsoft windows_xp — cpe:2.3:o:microsoft:windows_xp:*:sp2:professional:*:*:*:*:*
microsoft windows_xp — cpe:2.3:o:microsoft:windows_xp:*:sp3:*:*:*:*:*:*

References for CVE-2009-1926

cvelogic Threat Intelligence