{"cve":"CVE-2009-4444","nvd":{"published":"2009-12-29T21:00:24.327","modified":"2026-06-16T23:13:40.793","status":"Modified","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.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["http://blogs.technet.com/msrc/archive/2009/12/27/new-reports-of-a-vulnerability-in-iis.aspx","http://secunia.com/advisories/37831","http://securitytracker.com/id?1023387","http://soroush.secproject.com/downloadable/iis-semicolon-report.pdf","http://www.securityfocus.com/bid/37460"],"products":["microsoft:internet_information_services"],"source":"nvd","synced_at":"2026-10-19T19:55:32.599380760+00:00"},"epss":{"cve":"CVE-2009-4444","score":0.63627,"percentile":0.99215,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}