How severe is CVE-2009-0086?

CVE-2009-0086 has a CVSS 2.0 base score of 10.0, rated critical severity.

Is CVE-2009-0086 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 14% (96th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2009-0086?

CVE-2009-0086 primarily affects Microsoft Windows 2000. In total, 15 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2009-0086?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2009-0086 published?

CVE-2009-0086 was published on 2009-04-15 and last updated on 2026-06-16.

CVE-2009-0086

CVE-2009-0086 is a critical-severity vulnerability in Microsoft Windows 2000 with a CVSS 2.0 base score of 10.0. Its EPSS exploit-prediction score of 14% places it in the 96th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-189.

Key facts

Severity: Critical (CVSS 2.0 base score 10.0)
EPSS exploit prediction: 14% (96th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-189
Affected product: Microsoft Windows 2000
Published: 2009-04-15
Last modified: 2026-06-16

Description

Integer underflow in 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 allows remote HTTP servers to execute arbitrary code via crafted parameter values in a response, related to error handling, aka "Windows HTTP Services Integer Underflow Vulnerability."

Frequently asked questions

What is CVE-2009-0086?: Integer underflow in 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 allows remote HTTP servers to execute arbitrary code via crafted parameter values in a response, related to error handling, aka "Windows HTTP Services Integer Underflow Vulnerability."
How severe is CVE-2009-0086?: CVE-2009-0086 has a CVSS 2.0 base score of 10.0, rated critical severity.
Is CVE-2009-0086 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 14% (96th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-0086?: CVE-2009-0086 primarily affects Microsoft Windows 2000. In total, 15 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2009-0086?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2009-0086 published?: CVE-2009-0086 was published on 2009-04-15 and last updated on 2026-06-16.

References

Affected products (15)

cpe:2.3:o:microsoft:windows_2000:*:sp4:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2003:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2003:*:sp1:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2003:*:sp1:itanium:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2003:*:sp2:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:*:*:32_bit:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:*:*:itanium:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:*:*:x64:*:*:*:*:*
cpe:2.3:o:microsoft:windows_vista:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_vista:*:*:x64:*:*:*:*:*
cpe:2.3:o:microsoft:windows_vista:*:sp1:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_vista:gold:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_xp:*:sp2:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_xp:*:sp3:*:*:*:*:*:*

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