Unrated severityNVD Advisory· Published Dec 29, 2009· Updated Jun 16, 2026
CVE-2009-4444
CVE-2009-4444
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
3cpe:2.3:a:microsoft:internet_information_services:5.0:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:a:microsoft:internet_information_services:5.0:*:*:*:*:*:*:*
- cpe:2.3:a:microsoft:internet_information_services:6.0:*:*:*:*:*:*:*
- (no CPE)range: 5.x, 6.x
Patches
Vulnerability mechanics
References
6- secunia.com/advisories/37831nvdThird Party Advisory
- securitytracker.com/idnvdThird Party AdvisoryVDB Entry
- soroush.secproject.com/downloadable/iis-semicolon-report.pdfnvdThird Party Advisory
- www.securityfocus.com/bid/37460nvdThird Party AdvisoryVDB Entry
- www.vupen.com/english/advisories/2009/3634nvdThird Party Advisory
- blogs.technet.com/msrc/archive/2009/12/27/new-reports-of-a-vulnerability-in-iis.aspxnvdBroken Link
News mentions
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