{"cve":"CVE-2009-0033","nvd":{"published":"2009-06-05T16:00:00.187","modified":"2026-06-16T23:04:07.803","status":"Modified","description":"Apache Tomcat 4.1.0 through 4.1.39, 5.5.0 through 5.5.27, and 6.0.0 through 6.0.18, when the Java AJP connector and mod_jk load balancing are used, allows remote attackers to cause a denial of service (application outage) via a crafted request with invalid headers, related to temporary blocking of connectors that have encountered errors, as demonstrated by an error involving a malformed HTTP Host header.","cvss_v4":null,"cvss_v3":null,"cwes":["CWE-20"],"references":["http://jvn.jp/en/jp/JVN87272440/index.html","http://lists.apple.com/archives/security-announce/2010//Mar/msg00001.html","http://lists.opensuse.org/opensuse-security-announce/2009-07/msg00002.html","http://marc.info/?l=bugtraq&m=127420533226623&w=2","http://marc.info/?l=bugtraq&m=129070310906557&w=2"],"products":["apache:tomcat"],"source":"nvd","synced_at":"2026-10-19T19:54:07.895733559+00:00"},"epss":{"cve":"CVE-2009-0033","score":0.10053,"percentile":0.95622,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-5cw4-ggx9-36vg","url":"https://osv.dev/vulnerability/GHSA-5cw4-ggx9-36vg","summary":"Apache Tomcat Denial of Service via Malformed Request Headers","modified":"2024-01-23T18:11:45.013010Z","packages":[{"ecosystem":"Maven","name":"org.apache.tomcat:tomcat","purl":"pkg:maven/org.apache.tomcat/tomcat","ranges":[">=4.1.0 <=4.1.39"],"fixed":[]},{"ecosystem":"Maven","name":"org.apache.tomcat:tomcat","purl":"pkg:maven/org.apache.tomcat/tomcat","ranges":[">=5.5.0 <=5.5.27"],"fixed":[]},{"ecosystem":"Maven","name":"org.apache.tomcat:tomcat","purl":"pkg:maven/org.apache.tomcat/tomcat","ranges":[">=6.0.0 <=6.0.18"],"fixed":[]}]}],"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."]}