CVE-2009-0091

Microsoft .NET Framework 2.0, 2.0 SP1, and 3.5 does not properly enforce a certain type-equality constraint in .NET verifiable code, which allows remote attackers to execute arbitrary code via (1) a crafted XAML browser application (XBAP), (2) a crafted ASP.NET application, or (3) a crafted .NET Framework application, aka "Microsoft .NET Framework Type Verification Vulnerability."

Published: 2009-10-14 Last update: 2026-04-23 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2009-0091 is rated High Risk (67.4/100): CVSS Critical severity, with high exploitation likelihood (EPSS 38.21%, 97th 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-2009-0091

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 2026-05-02 42.01% 38.21% -3.79%
2 2026-03-05 44.52% 42.01% -2.51%
3 2025-12-28 — 44.52% —

Full EPSS history (33 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2009-0091

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.3 2.0 HIGH
AV:N/AC:M/Au:N/C:C/I:C/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
 8.6 10.0 [email protected]

Weakness enumeration for CVE-2009-0091

Affected software / configurations for CVE-2009-0091

Vendor Product Version Raw CPE
microsoft windows_2000 — cpe:2.3:o:microsoft:windows_2000:*:sp4:*:*:*:*:*:*
microsoft .net_framework 1.1 cpe:2.3:a:microsoft:.net_framework:1.1:sp1:*:*:*:*:*:*
microsoft .net_framework 2.0 cpe:2.3:a:microsoft:.net_framework:2.0:sp1:*:*:*:*:*:*
microsoft .net_framework 2.0 cpe:2.3:a:microsoft:.net_framework:2.0:sp2:*:*:*:*:*:*
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:*:*:*:*:*:*
microsoft windows_server_2008 — cpe:2.3:o:microsoft:windows_server_2008:-:sp2:x86:*:*:*:*:*
microsoft .net_framework 3.5 cpe:2.3:a:microsoft:.net_framework:3.5:*:*:*:*:*:*:*
microsoft .net_framework 3.5 cpe:2.3:a:microsoft:.net_framework:3.5:sp1:*:*:*:*:*:*
microsoft windows_vista — cpe:2.3:o:microsoft:windows_vista:*:*:*:*:*:*:*:*
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 .net_framework 2.0 cpe:2.3:a:microsoft:.net_framework:2.0:*:*:*:*:*:*:*
microsoft windows_7 — cpe:2.3:o:microsoft:windows_7:-:*:*:*:*:*:*:*
microsoft windows_server_2008 — cpe:2.3:o:microsoft:windows_server_2008:*:r2:itanium:*:*:*:*:*
microsoft windows_server_2008 — cpe:2.3:o:microsoft:windows_server_2008:*:r2:x64:*:*:*:*:*
microsoft .net_framework 1.0 cpe:2.3:a:microsoft:.net_framework:1.0:sp3:*:*:*:*:*:*
microsoft windows_xp — cpe:2.3:o:microsoft:windows_xp:*:sp2:*:*:*:*:*:*
microsoft windows_xp — cpe:2.3:o:microsoft:windows_xp:*:sp3:*:*:*:*:*:*
microsoft windows_xp — cpe:2.3:o:microsoft:windows_xp:-:sp2:x64:*:*:*:*:*

References for CVE-2009-0091

cvelogic Threat Intelligence