CVE-2009-4445
Microsoft Internet Information Services (IIS), when used in conjunction with unspecified third-party upload applications, allows remote attackers to create empty files with arbitrary extensions via a filename containing an initial extension followed by a : (colon) and a safe extension, as demonstrated by an upload of a .asp:.jpg file that results in creation of an empty .asp file, related to support for the NTFS Alternate Data Streams (ADS) filename syntax. NOTE: it could be argued that this is a vulnerability in the third-party product, not IIS, because the third-party product should be applying its extension restrictions to the portion of the filename before the colon.
Key facts
- CVSS score
- 6.0 (v2.0)
- Severity
- MEDIUM
- CVSS vector
AV:N/AC:M/Au:S/C:P/I:P/A:P- Weakness (CWE)
- CWE-20
- EPSS score
- 12.8% (96th percentile)
- In CISA KEV
- No
- In EU EUVD
- Yes (EUVD-2009-4412)
- 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-2009-4412 in the EU Vulnerability Database. Last updated in EUVD on August 7, 2024.
View on the EU Vulnerability DatabaseAffected products
- microsoft / internet information services
References
- http://securitytracker.com/id?1023387(Third Party Advisory, VDB Entry)
- http://soroush.secproject.com/downloadable/iis-semicolon-report.pdf(Third Party Advisory)
- https://exchange.xforce.ibmcloud.com/vulnerabilities/55308
Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS
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