CVE-2009-3720

Name: CVE-2009-3720
Creator: NVD / NIST
Published: 2009-11-03T16:30:12.563+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

UnknownEPSS 27.92%

Last modified Jun 16, 2026

CVE-2009-3720 is a vulnerability of currently unknown severity. 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.. EPSS estimates a 27.92% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability

27.92%

97.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Libexpat Project	Libexpat	2.0.1
Apache	Http Server	>= 2.0.35, < 2.0.64
Apache	Http Server	>= 2.2.0, < 2.2.17

References

http://expat.cvs.sourceforge.net/viewvc/expat/expat/lib/xmltok_impl.c?r1=1.13&r2=1.15&view=patchExploit
http://expat.cvs.sourceforge.net/viewvc/expat/expat/lib/xmltok_impl.c?view=logMailing List, Third Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051228.htmlThird Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051247.htmlMailing List, Third Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051367.htmlThird Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051405.htmlThird Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051442.htmlThird Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2009-11/msg00004.htmlThird Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2010-05/msg00001.htmlThird Party Advisory, VDB Entry
http://lists.opensuse.org/opensuse-security-announce/2010-05/msg00002.htmlThird Party Advisory, VDB Entry
http://lists.opensuse.org/opensuse-security-announce/2010-06/msg00001.htmlThird Party Advisory, VDB Entry
http://lists.opensuse.org/opensuse-security-announce/2010-08/msg00001.htmlThird Party Advisory, VDB Entry
http://lists.vmware.com/pipermail/security-announce/2010/000082.htmlBroken Link
http://mail.python.org/pipermail/expat-bugs/2009-January/002781.htmlThird Party Advisory
http://marc.info/?l=bugtraq&m=130168502603566&w=2Mailing List, Third Party Advisory
http://secunia.com/advisories/37324Broken Link
http://secunia.com/advisories/37537Broken Link
http://secunia.com/advisories/37925Broken Link
http://secunia.com/advisories/38050Broken Link
http://secunia.com/advisories/38231Broken Link
http://secunia.com/advisories/38794Broken Link
http://secunia.com/advisories/38832Broken Link
http://secunia.com/advisories/38834Broken Link
http://secunia.com/advisories/39478Broken Link
http://secunia.com/advisories/41701Broken Link
http://secunia.com/advisories/42326Broken Link
http://secunia.com/advisories/42338Broken Link
http://secunia.com/advisories/43300Broken Link
http://slackware.com/security/viewer.php?l=slackware-security&y=2011&m=slackware-security.486026Mailing List, Third Party Advisory
http://sourceforge.net/tracker/index.php?func=detail&aid=1990430&group_id=10127&atid=110127Mailing List, Third Party Advisory
http://sunsolve.sun.com/search/document.do?assetkey=1-66-273630-1Broken Link
http://svn.python.org/view?view=rev&revision=74429Permissions Required, Third Party Advisory
http://www.mandriva.com/security/advisories?name=MDVSA-2009:211Permissions Required, Third Party Advisory
http://www.mandriva.com/security/advisories?name=MDVSA-2009:212Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:215Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:216Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:217Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:218Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:219Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:220Broken Link
http://www.openwall.com/lists/oss-security/2009/08/21/2Mailing List
http://www.openwall.com/lists/oss-security/2009/08/26/3Mailing List
http://www.openwall.com/lists/oss-security/2009/08/26/4Mailing List
http://www.openwall.com/lists/oss-security/2009/08/27/6Mailing List
http://www.openwall.com/lists/oss-security/2009/09/06/1Mailing List
http://www.openwall.com/lists/oss-security/2009/10/22/5Mailing List
http://www.openwall.com/lists/oss-security/2009/10/22/9Mailing List
http://www.openwall.com/lists/oss-security/2009/10/23/2Mailing List
http://www.openwall.com/lists/oss-security/2009/10/23/6Mailing List
http://www.openwall.com/lists/oss-security/2009/10/26/3Mailing List
http://www.openwall.com/lists/oss-security/2009/10/28/3Mailing List
http://www.redhat.com/support/errata/RHSA-2010-0002.htmlBroken Link
http://www.redhat.com/support/errata/RHSA-2011-0896.htmlBroken Link
http://www.securitytracker.com/id?1023160Third Party Advisory, VDB Entry
http://www.ubuntu.com/usn/USN-890-1Third Party Advisory
http://www.ubuntu.com/usn/USN-890-6Third Party Advisory
http://www.vupen.com/english/advisories/2010/0528Broken Link
http://www.vupen.com/english/advisories/2010/0896Broken Link
http://www.vupen.com/english/advisories/2010/1107Broken Link
http://www.vupen.com/english/advisories/2010/3035Broken Link
http://www.vupen.com/english/advisories/2010/3053Broken Link
http://www.vupen.com/english/advisories/2010/3061Broken Link
http://www.vupen.com/english/advisories/2011/0359Broken Link
https://bugs.gentoo.org/show_bug.cgi?id=280615Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=531697Issue Tracking
https://lists.apache.org/thread.html/54a42d4b01968df1117cea77fc53d6beb931c0e05936ad02af93e9ac%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/5df9bfb86a3b054bb985a45ff9250b0332c9ecc181eec232489e7f79%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/8d63cb8e9100f28a99429b4328e4e7cebce861d5772ac9863ba2ae6f%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/f7f95ac1cd9895db2714fa3ebaa0b94d0c6df360f742a40951384a53%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r0276683d8e1e07153fc8642618830ac0ade85b9ae0dc7b07f63bb8fc%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r2295080a257bad27ea68ca0af12fc715577f9e84801eae116a33107e%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r2cb985de917e7da0848c440535f65a247754db8b2154a10089e4247b%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r476d175be0aaf4a17680ef98c5153b4d336eaef76fb2224cc94c463a%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r57608dc51b79102f3952ae06f54d5277b649c86d6533dcd6a7d201f7%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r5f9c22f9c28adbd9f00556059edc7b03a5d5bb71d4bb80257c0d34e4%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r75cbe9ea3e2114e4271bbeca7aff96117b50c1b6eb7c4772b0337c1f%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r8828e649175df56f1f9e3919938ac7826128525426e2748f0ab62feb%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r9e8622254184645bc963a1d47c5d47f6d5a36d6f080d8d2c43b2b142%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r9ea3538f229874c80a10af473856a81fbf5f694cd7f471cc679ba70b%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r9f93cf6dde308d42a9c807784e8102600d0397f5f834890708bf6920%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/rad01d817195e6cc871cb1d73b207ca326379a20a6e7f30febaf56d24%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/rad2acee3ab838b52c04a0698b1728a9a43467bf365bd481c993c535d%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/rb9c9f42dafa25d2f669dac2a536a03f2575bc5ec1be6f480618aee10%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/rdca61ae990660bacb682295f2a09d34612b7bb5f457577fe17f4d064%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/reb7c64aeea604bf948467d9d1cab8ff23fa7d002be1964bcc275aae7%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/rf6449464fd8b7437704c55f88361b66f12d5b5f90bcce66af4be4ba9%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/rfbaf647d52c1cb843e726a0933f156366a806cead84fbd430951591b%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11019Broken Link
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12719Broken Link
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A7112Mailing List, Third Party Advisory
https://www.redhat.com/archives/fedora-package-announce/2009-December/msg00370.htmlThird Party Advisory
https://www.redhat.com/archives/fedora-package-announce/2009-December/msg00413.htmlThird Party Advisory
https://www.redhat.com/archives/fedora-package-announce/2009-December/msg01274.htmlThird Party Advisory
http://expat.cvs.sourceforge.net/viewvc/expat/expat/lib/xmltok_impl.c?r1=1.13&r2=1.15&view=patchExploit
http://expat.cvs.sourceforge.net/viewvc/expat/expat/lib/xmltok_impl.c?view=logMailing List, Third Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051228.htmlThird Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051247.htmlMailing List, Third Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051367.htmlThird Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051405.htmlThird Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/051442.htmlThird Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2009-11/msg00004.htmlThird Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2010-05/msg00001.htmlThird Party Advisory, VDB Entry
http://lists.opensuse.org/opensuse-security-announce/2010-05/msg00002.htmlThird Party Advisory, VDB Entry
http://lists.opensuse.org/opensuse-security-announce/2010-06/msg00001.htmlThird Party Advisory, VDB Entry
http://lists.opensuse.org/opensuse-security-announce/2010-08/msg00001.htmlThird Party Advisory, VDB Entry
http://lists.vmware.com/pipermail/security-announce/2010/000082.htmlBroken Link
http://mail.python.org/pipermail/expat-bugs/2009-January/002781.htmlThird Party Advisory
http://marc.info/?l=bugtraq&m=130168502603566&w=2Mailing List, Third Party Advisory
http://secunia.com/advisories/37324Broken Link
http://secunia.com/advisories/37537Broken Link
http://secunia.com/advisories/37925Broken Link
http://secunia.com/advisories/38050Broken Link
http://secunia.com/advisories/38231Broken Link
http://secunia.com/advisories/38794Broken Link
http://secunia.com/advisories/38832Broken Link
http://secunia.com/advisories/38834Broken Link
http://secunia.com/advisories/39478Broken Link
http://secunia.com/advisories/41701Broken Link
http://secunia.com/advisories/42326Broken Link
http://secunia.com/advisories/42338Broken Link
http://secunia.com/advisories/43300Broken Link
http://slackware.com/security/viewer.php?l=slackware-security&y=2011&m=slackware-security.486026Mailing List, Third Party Advisory
http://sourceforge.net/tracker/index.php?func=detail&aid=1990430&group_id=10127&atid=110127Mailing List, Third Party Advisory
http://sunsolve.sun.com/search/document.do?assetkey=1-66-273630-1Broken Link
http://svn.python.org/view?view=rev&revision=74429Permissions Required, Third Party Advisory
http://www.mandriva.com/security/advisories?name=MDVSA-2009:211Permissions Required, Third Party Advisory
http://www.mandriva.com/security/advisories?name=MDVSA-2009:212Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:215Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:216Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:217Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:218Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:219Broken Link
http://www.mandriva.com/security/advisories?name=MDVSA-2009:220Broken Link
http://www.openwall.com/lists/oss-security/2009/08/21/2Mailing List
http://www.openwall.com/lists/oss-security/2009/08/26/3Mailing List
http://www.openwall.com/lists/oss-security/2009/08/26/4Mailing List
http://www.openwall.com/lists/oss-security/2009/08/27/6Mailing List
http://www.openwall.com/lists/oss-security/2009/09/06/1Mailing List
http://www.openwall.com/lists/oss-security/2009/10/22/5Mailing List
http://www.openwall.com/lists/oss-security/2009/10/22/9Mailing List
http://www.openwall.com/lists/oss-security/2009/10/23/2Mailing List
http://www.openwall.com/lists/oss-security/2009/10/23/6Mailing List
http://www.openwall.com/lists/oss-security/2009/10/26/3Mailing List
http://www.openwall.com/lists/oss-security/2009/10/28/3Mailing List
http://www.redhat.com/support/errata/RHSA-2010-0002.htmlBroken Link
http://www.redhat.com/support/errata/RHSA-2011-0896.htmlBroken Link
http://www.securitytracker.com/id?1023160Third Party Advisory, VDB Entry
http://www.ubuntu.com/usn/USN-890-1Third Party Advisory
http://www.ubuntu.com/usn/USN-890-6Third Party Advisory
http://www.vupen.com/english/advisories/2010/0528Broken Link
http://www.vupen.com/english/advisories/2010/0896Broken Link
http://www.vupen.com/english/advisories/2010/1107Broken Link
http://www.vupen.com/english/advisories/2010/3035Broken Link
http://www.vupen.com/english/advisories/2010/3053Broken Link
http://www.vupen.com/english/advisories/2010/3061Broken Link
http://www.vupen.com/english/advisories/2011/0359Broken Link
https://bugs.gentoo.org/show_bug.cgi?id=280615Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=531697Issue Tracking
https://lists.apache.org/thread.html/54a42d4b01968df1117cea77fc53d6beb931c0e05936ad02af93e9ac%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/5df9bfb86a3b054bb985a45ff9250b0332c9ecc181eec232489e7f79%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/8d63cb8e9100f28a99429b4328e4e7cebce861d5772ac9863ba2ae6f%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/f7f95ac1cd9895db2714fa3ebaa0b94d0c6df360f742a40951384a53%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r0276683d8e1e07153fc8642618830ac0ade85b9ae0dc7b07f63bb8fc%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r2295080a257bad27ea68ca0af12fc715577f9e84801eae116a33107e%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r2cb985de917e7da0848c440535f65a247754db8b2154a10089e4247b%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r476d175be0aaf4a17680ef98c5153b4d336eaef76fb2224cc94c463a%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r57608dc51b79102f3952ae06f54d5277b649c86d6533dcd6a7d201f7%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r5f9c22f9c28adbd9f00556059edc7b03a5d5bb71d4bb80257c0d34e4%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r75cbe9ea3e2114e4271bbeca7aff96117b50c1b6eb7c4772b0337c1f%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r8828e649175df56f1f9e3919938ac7826128525426e2748f0ab62feb%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r9e8622254184645bc963a1d47c5d47f6d5a36d6f080d8d2c43b2b142%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r9ea3538f229874c80a10af473856a81fbf5f694cd7f471cc679ba70b%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/r9f93cf6dde308d42a9c807784e8102600d0397f5f834890708bf6920%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/rad01d817195e6cc871cb1d73b207ca326379a20a6e7f30febaf56d24%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/rad2acee3ab838b52c04a0698b1728a9a43467bf365bd481c993c535d%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/rb9c9f42dafa25d2f669dac2a536a03f2575bc5ec1be6f480618aee10%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/rdca61ae990660bacb682295f2a09d34612b7bb5f457577fe17f4d064%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/reb7c64aeea604bf948467d9d1cab8ff23fa7d002be1964bcc275aae7%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/rf6449464fd8b7437704c55f88361b66f12d5b5f90bcce66af4be4ba9%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://lists.apache.org/thread.html/rfbaf647d52c1cb843e726a0933f156366a806cead84fbd430951591b%40%3Ccvs.httpd.apache.org%3EThird Party Advisory
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11019Broken Link
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12719Broken Link
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A7112Mailing List, Third Party Advisory
https://www.redhat.com/archives/fedora-package-announce/2009-December/msg00370.htmlThird Party Advisory
https://www.redhat.com/archives/fedora-package-announce/2009-December/msg00413.htmlThird Party Advisory
https://www.redhat.com/archives/fedora-package-announce/2009-December/msg01274.htmlThird Party Advisory

Timeline

Published: Nov 3, 2009
Last Modified: Jun 16, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2009-3720?

How severe is CVE-2009-3720?

Severity scoring for CVE-2009-3720 is pending analysis. The EPSS model estimates a 27.92% probability of exploitation in the next 30 days.

How do I fix CVE-2009-3720?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2009-3720?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST