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…
- 6.0MediumCVSS base score
- 63.6%Exploitation in 30 daysEPSS · top 0.8% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By mitre
Published
- 15 years later
· 15 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 2.0 | Medium6.0 | AV:N/AC:M/Au:S/C:P/I:P/A:P |
- EPSS (exploitation in 30 days)
- 63.6% · top 0.8% of all CVEs (11 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.0.
Affected products
n/a
- affected n/a
References
References6
- 37460 (opens in a new tab)vdb-entryx_refsource_BIDx_transferred
- 1023387 (opens in a new tab)vdb-entryx_refsource_SECTRACKx_transferred
- http://blogs.technet.com/msrc/archive/2009/12/27/new-reports-of-a-vulnerability-in-iis.aspx (opens in a new tab)x_refsource_MISCx_transferred
- 37831 (opens in a new tab)third-party-advisoryx_refsource_SECUNIAx_transferred
- http://soroush.secproject.com/downloadable/iis-semicolon-report.pdf (opens in a new tab)x_refsource_MISCx_transferred
- ADV-2009-3634 (opens in a new tab)vdb-entryx_refsource_VUPENx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2009-4411 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2009-4444)Record last updated .