CVE-2009-4444

critical

Description

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.

References

Details

Source: Mitre, NVD

Published: 2009-12-29

Updated: 2026-06-16

Risk Information

CVSS v2

Base Score: 6

Vector: CVSS2#AV:N/AC:M/Au:S/C:P/I:P/A:P

Severity: Medium

CVSS v3

Base Score: 9.1

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Severity: Critical

EPSS

EPSS: 0.63627