Is CVE-2009-0550 in the CISA KEV catalog?

No. CVE-2009-0550 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2009-0550?

CVE-2009-0550 has a CVSS v2 base score of 9.3 (HIGH).

What is the EPSS score for CVE-2009-0550?

CVE-2009-0550 has an EPSS score of 11.75% (96th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2009-0550

HIGHEPSS 96th pctl

9.3

CVSS v2

NVD

Description

Windows HTTP Services (aka WinHTTP) in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP1 and SP2, Vista Gold and SP1, and Server 2008; and WinINet in Microsoft Internet Explorer 5.01 SP4, 6 SP1, 6 and 7 on Windows XP SP2 and SP3, 6 and 7 on Windows Server 2003 SP1 and SP2, 7 on Windows Vista Gold and SP1, and 7 on Windows Server 2008; allows remote web servers to capture and replay NTLM credentials, and execute arbitrary code, via vectors related to absence of a "credential-reflection protections" opt-in step, aka "Windows HTTP Services Credential Reflection Vulnerability" and "WinINet Credential Reflection Vulnerability."

CVSS v2 Vector

No CVSS vector data available.

Exploit Intelligence

11.75%probability of exploitation in 30 days

96thpercentile

Very high risk: more likely to be exploited than 96% of all known CVEs.

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-23.