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CVE-2009-4444

Microsoft Internet Information Services (IIS) 5.x and 6.x uses only the portion of a filename...

6.0 Medium

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.

Exploit likelihood

63.6%Up 37.7 points since Feb 4, 2022
90%50%10%1%

What each source reports

NVD Score used 6.0

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.

Record
CVE-2009-4444
CVSS 2.0
6.0 MediumAV:N/AC:M/Au:S/C:P/I:P/A:P
Updated
2026-11-02
CVE List No score

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.

Record
CVE-2009-4444
Updated
2026-11-02
EUVDEUVD-2009-4411 No score

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.

Record
EUVD-2009-4411
Updated
2026-11-03
GitHub AdvisoriesGHSA-4jh7-wh4m-f4pq No score

Microsoft Internet Information Services (IIS) 5.x and 6.x uses only the portion of a filename...

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.

Record
GHSA-4jh7-wh4m-f4pq
Updated
2026-11-02

Affected products

History

History
RecordedChangedSources
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2009-4444 is a medium vulnerability (CVSS 6.0) in Microsoft Internet Information Services, published December 29, 2009. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 63.6%, the 99th percentile. No source names a fixed version.

References

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