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Vulnerability record · CVE-2009-3560 · published 4 December 2009

CVE-2009-3560: Libexpat project libexpat memory buffer overflow vulnerability

LLibexpat Project · Libexpat

The big2_toUtf8 function in lib/xmltok.c in libexpat in Expat 2.0.1, as used in the XML-Twig module for Perl, allows context-dependent attackers to cause a denial of service (application crash) via an XML document with malformed UTF-8 sequences that trigger a buffer over-read, related to the doProlog function in lib/xmlparse.c, a different vulnerability than CVE-2009-2625 and CVE-2009-3720.

5.0 CVSS 2.0 Medium EPSS 24% · top 2.2% CWE-119 · Memory buffer overflow
5.0CVSS 2.0 base score
24%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
116References, 2 tagged exploit
16 Jun 2026Last modified by NVD

Description

The big2_toUtf8 function in lib/xmltok.c in libexpat in Expat 2.0.1, as used in the XML-Twig module for Perl, allows context-dependent attackers to cause a denial of service (application crash) via an XML document with malformed UTF-8 sequences that trigger a buffer over-read, related to the doProlog function in lib/xmlparse.c, a different vulnerability than CVE-2009-2625 and CVE-2009-3720.

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/xmlparse.c?r1=1.164&r2=1.165 Permissions Required
http://expat.cvs.sourceforge.net/viewvc/expat/expat/lib/xmlparse.c?view=log#rev1.165 Broken Link
http://lists.opensuse.org/opensuse-security-announce/2010-01/msg00007.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-November/002846.html Exploit
http://marc.info/?l=bugtraq&m=130168502603566&w=2 Mailing ListThird Party Advisory
http://secunia.com/advisories/37537 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/43300 Broken Link
http://slackware.com/security/viewer.php?l=slackware-security&y=2011&m=slackware-security.486026 Mailing ListThird Party Advisory
http://sunsolve.sun.com/search/document.do?assetkey=1-66-273630-1 Mailing ListThird Party Advisory
http://www.debian.org/security/2009/dsa-1953 Third Party Advisory
http://www.mandriva.com/security/advisories?name=MDVSA-2009:316 Broken Link
http://www.redhat.com/support/errata/RHSA-2011-0896.html Broken Link
http://www.securityfocus.com/bid/37203 Third Party AdvisoryVDB Entry
http://www.securitytracker.com/id?1023278 Third Party AdvisoryVDB Entry
http://www.ubuntu.com/usn/USN-890-1 Third Party AdvisoryVDB Entry
http://www.ubuntu.com/usn/USN-890-6 Third Party Advisory
http://www.vupen.com/english/advisories/2010/0528 Broken Link
http://www.vupen.com/english/advisories/2010/0896 Broken Link
http://www.vupen.com/english/advisories/2010/1107 Broken Link
http://www.vupen.com/english/advisories/2011/0359 Broken Link
https://bugzilla.redhat.com/show_bug.cgi?id=533174 Issue TrackingPatch
https://lists.apache.org/thread.html/54a42d4b01968df1117cea77fc53d6beb931c0e05936ad02af93e9ac%40%3Ccvs.httpd.apache.org%
https://lists.apache.org/thread.html/5df9bfb86a3b054bb985a45ff9250b0332c9ecc181eec232489e7f79%40%3Ccvs.httpd.apache.org%
https://lists.apache.org/thread.html/8d63cb8e9100f28a99429b4328e4e7cebce861d5772ac9863ba2ae6f%40%3Ccvs.httpd.apache.org%
https://lists.apache.org/thread.html/f7f95ac1cd9895db2714fa3ebaa0b94d0c6df360f742a40951384a53%40%3Ccvs.httpd.apache.org%
https://lists.apache.org/thread.html/r0276683d8e1e07153fc8642618830ac0ade85b9ae0dc7b07f63bb8fc%40%3Ccvs.httpd.apache.org
https://lists.apache.org/thread.html/r2295080a257bad27ea68ca0af12fc715577f9e84801eae116a33107e%40%3Ccvs.httpd.apache.org
https://lists.apache.org/thread.html/r2cb985de917e7da0848c440535f65a247754db8b2154a10089e4247b%40%3Ccvs.httpd.apache.org
https://lists.apache.org/thread.html/r57608dc51b79102f3952ae06f54d5277b649c86d6533dcd6a7d201f7%40%3Ccvs.httpd.apache.org

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Source: NIST National Vulnerability Database (record CVE-2009-3560), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.