{"id":"CVE-2009-4444","url":"https://www.cyber-defence.io/tools/cve/CVE-2009-4444","generatedAt":"2026-10-27T19:39:32.343Z","title":"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…","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.","published":"2009-12-29T21:00:24.000Z","lastModified":"2026-06-16T23:13:41.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"2.0","score":6,"severity":"MEDIUM","vector":"AV:N/AC:M/Au:S/C:P/I:P/A:P"},"cwe":[],"affected":["microsoft/internet information services"],"epss":{"score":0.63627,"percentile":0.9921,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"EPSS puts the probability of exploitation in the next 30 days at 63.6%, higher than 99% of all known CVEs. Patch or mitigate before the next change window."},"changes":[],"references":[{"url":"http://blogs.technet.com/msrc/archive/2009/12/27/new-reports-of-a-vulnerability-in-iis.aspx","tags":["Broken Link"],"source":"cve@mitre.org"},{"url":"http://secunia.com/advisories/37831","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://securitytracker.com/id?1023387","tags":["Third Party Advisory","VDB Entry"],"source":"cve@mitre.org"},{"url":"http://soroush.secproject.com/downloadable/iis-semicolon-report.pdf","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.securityfocus.com/bid/37460","tags":["Third Party Advisory","VDB Entry"],"source":"cve@mitre.org"},{"url":"http://www.vupen.com/english/advisories/2009/3634","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://blogs.technet.com/msrc/archive/2009/12/27/new-reports-of-a-vulnerability-in-iis.aspx","tags":["Broken Link"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://secunia.com/advisories/37831","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://securitytracker.com/id?1023387","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://soroush.secproject.com/downloadable/iis-semicolon-report.pdf","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securityfocus.com/bid/37460","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.vupen.com/english/advisories/2009/3634","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2009-4444","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}