CVE•Published 2009-11-03•Modified 2026-07-20•1 article on news•6 live references•NVD data
CVE-2009-3720Libexpat_project · Libexpat
Vulnerability data via NVD (ingested)
CVSS v3.1
—
EPSS percentile
98
Exploit Prediction Scoring System · top 2% of all CVEs
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.
Timeline
Published 2009-11-03
Modified 2026-07-20
External references
Search for exposed instances
Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).
Shodan · vuln tag1,616,185 hosts
vuln:CVE-2009-3720Hosts Shodan has explicitly fingerprinted as vulnerable.
Shodan · product + version
product:"Libexpat Project Libexpat" version:"2.0.1"Version-pinned fingerprint from NVD's first vulnerable CPE.
Shodan · banner/body mention
http.html:"Libexpat"HTTP body or banner mentions "Libexpat" — catches deploys Shodan didn't identify as a product.
More intel sources (5)
Shodan report
vuln:CVE-2009-3720Country / ASN / product breakdown for the vuln query.
Censys
vulnerabilities.cve_id: CVE-2009-3720Censys host search filtered to this CVE id.
grep.app
CVE-2009-3720Public source-code mentions — fast PoC discovery.
GitHub code
CVE-2009-3720GitHub code search for direct mentions.
Google dork
"CVE-2009-3720" exploit -site:nvd.nist.govWrite-ups and news, NVD excluded.