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.
Key facts
- CVSS score
- 6.0 (v2.0)
- Severity
- MEDIUM
- CVSS vector
AV:N/AC:M/Au:S/C:P/I:P/A:P- EPSS score
- 63.6% (99th percentile)
- In CISA KEV
- No
- In EU EUVD
- Yes (EUVD-2009-4411)
- Published
- December 29, 2009
- NVD last modified
- June 16, 2026
- Status
- Modified
EU Vulnerability Database (EUVD)
This vulnerability is also tracked by ENISA as EUVD-2009-4411 in the EU Vulnerability Database. Last updated in EUVD on September 16, 2024.
View on the EU Vulnerability DatabaseAffected products
- microsoft / internet information services
- microsoft / internet information services
References
- http://blogs.technet.com/msrc/archive/2009/12/27/new-reports-of-a-vulnerability-in-iis.aspx(Broken Link)
- http://secunia.com/advisories/37831(Third Party Advisory)
- http://securitytracker.com/id?1023387(Third Party Advisory, VDB Entry)
- http://soroush.secproject.com/downloadable/iis-semicolon-report.pdf(Third Party Advisory)
- http://www.securityfocus.com/bid/37460(Third Party Advisory, VDB Entry)
- http://www.vupen.com/english/advisories/2009/3634(Third Party Advisory)
Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS
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