{"cve":"CVE-2009-3720","nvd":{"published":"2009-11-03T16:30:12.563","modified":"2026-07-20T14:35:41.700","status":"Modified","description":"The updatePosition function in lib/xmltok_impl.c in libexpat in Expat 2.0.1, as used in Python, PyXML, w3c-libwww, and other software, allows context-dependent attackers to cause a denial of service (application crash) via an XML document with crafted UTF-8 sequences that trigger a buffer over-read, a different vulnerability than CVE-2009-2625.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["http://expat.cvs.sourceforge.net/viewvc/expat/expat/lib/xmltok_impl.c?r1=1.13&r2=1.15&view=patch","http://expat.cvs.sourceforge.net/viewvc/expat/expat/lib/xmltok_impl.c?view=log","http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051228.html","http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051247.html","http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051367.html"],"products":["apache:http_server","libexpat_project:libexpat"],"source":"nvd","synced_at":"2026-10-19T19:54:26.868835795+00:00"},"epss":{"cve":"CVE-2009-3720","score":0.27924,"percentile":0.98099,"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."]}