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Vulnerability record · CVE-2009-3720 · published 3 November 2009

CVE-2009-3720: Libexpat project libexpat vulnerability

LLibexpat Project · Libexpat

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.

5.0 CVSS 2.0 Medium EPSS 28% · top 2.0%
5.0CVSS 2.0 base score
28%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
186References, 2 tagged exploit
20 Jul 2026Last modified by NVD

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.

AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://expat.cvs.sourceforge.net/viewvc/expat/expat/lib/xmltok_impl.c?r1=1.13&r2=1.15&view=patch Exploit
http://expat.cvs.sourceforge.net/viewvc/expat/expat/lib/xmltok_impl.c?view=log Mailing ListThird Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051228.html Third Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051247.html Mailing ListThird Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051367.html Third Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051405.html Third Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051442.html Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2009-11/msg00004.html Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2010-05/msg00001.html Third Party AdvisoryVDB Entry
http://lists.opensuse.org/opensuse-security-announce/2010-05/msg00002.html Third Party AdvisoryVDB Entry
http://lists.opensuse.org/opensuse-security-announce/2010-06/msg00001.html Third Party AdvisoryVDB Entry
http://lists.opensuse.org/opensuse-security-announce/2010-08/msg00001.html Third Party AdvisoryVDB Entry
http://lists.vmware.com/pipermail/security-announce/2010/000082.html Broken Link
http://mail.python.org/pipermail/expat-bugs/2009-January/002781.html Third Party Advisory
http://marc.info/?l=bugtraq&m=130168502603566&w=2 Mailing ListThird Party Advisory
http://secunia.com/advisories/37324 Broken Link
http://secunia.com/advisories/37537 Broken Link
http://secunia.com/advisories/37925 Broken Link
http://secunia.com/advisories/38050 Broken Link
http://secunia.com/advisories/38231 Broken Link
http://secunia.com/advisories/38794 Broken Link
http://secunia.com/advisories/38832 Broken Link
http://secunia.com/advisories/38834 Broken Link
http://secunia.com/advisories/39478 Broken Link
http://secunia.com/advisories/41701 Broken Link
http://secunia.com/advisories/42326 Broken Link
http://secunia.com/advisories/42338 Broken Link
http://secunia.com/advisories/43300 Broken Link
http://slackware.com/security/viewer.php?l=slackware-security&y=2011&m=slackware-security.486026 Mailing ListThird Party Advisory
http://sourceforge.net/tracker/index.php?func=detail&aid=1990430&group_id=10127&atid=110127 Mailing ListThird Party Advisory
http://sunsolve.sun.com/search/document.do?assetkey=1-66-273630-1 Broken Link
http://svn.python.org/view?view=rev&revision=74429 Permissions RequiredThird Party Advisory
http://www.mandriva.com/security/advisories?name=MDVSA-2009:211 Permissions RequiredThird Party Advisory
http://www.mandriva.com/security/advisories?name=MDVSA-2009:212 Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:215 Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:216 Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:217 Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:218 Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:219 Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:220 Broken Link

Track CVE-2009-3720 inside VULONE

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Source: NIST National Vulnerability Database (record CVE-2009-3720), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.