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.
Official description from the CVE record, published by mitre. Copyright © 1999-2026 The MITRE Corporation. See /security/cve/legal for the CVE license. View the record on cve.org
Key data
EPSS
- Score
- 0.63627 (63.6% probability)
- Percentile
- 99.2%
- Scores of
- Nov 10, 2026
- Model
- v2026.06.15
References
- 37460 (securityfocus.com)vdb-entry
- 1023387 (securitytracker.com)vdb-entry
- blogs.technet.com/msrc/archive/2009/12/27/new-reports-of-a-…
- 37831 (secunia.com)third-party-advisory
- soroush.secproject.com/downloadable/iis-semicolon-report.pdf
- ADV-2009-3634 (vupen.com)vdb-entry
Timeline
- ID reserved
- Record published
- Record last updated
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About CubePath
Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 19:49 UTC. Sources and licenses