CVE-2009-4444

Microsoft Internet Information Services (IIS) 5.x and 6.x uses only the portion of a filename before a ; (semicolon) character to determine the file extension, which allows remote attackers to bypass intended extension restrictions of third-party upload applications via a filename with a (1) .asp, (2) .cer, or (3) .asa first extension, followed by a semicolon and a safe extension, as demonstrated by the use of asp.dll to handle a .asp;.jpg file.

Published: 2009-12-29 Last update: 2026-04-23 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2009-4444 is rated Moderate Risk (63.7/100): CVSS Medium severity, with high exploitation likelihood (EPSS 63.63%, 99th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +5.04% over the last day, indicating growing attacker interest. 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-2009-4444

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 2026-06-15 58.58% 63.63% +5.04%
2 2026-03-04 49.26% 58.58% +9.33%
3 2026-03-01 — 49.26% —

Full EPSS history (48 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2009-4444

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.0 2.0 MEDIUM
AV:N/AC:M/Au:S/C:P/I:P/A:P 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:S)
A single authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 6.8 6.4 [email protected]

Weakness enumeration for CVE-2009-4444

Affected software / configurations for CVE-2009-4444

Vendor Product Version Raw CPE
microsoft internet_information_services 5.0 cpe:2.3:a:microsoft:internet_information_services:5.0:*:*:*:*:*:*:*
microsoft internet_information_services 6.0 cpe:2.3:a:microsoft:internet_information_services:6.0:*:*:*:*:*:*:*

References for CVE-2009-4444

cvelogic Threat Intelligence