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CVE-2009-3720

35
FAUCET Score

CVE-2009-3720 describes a denial-of-service vulnerability in libexpat 2.0.1, affecting products like Python and Apache, where crafted UTF-8 sequences in an XML document can cause an application crash due to a buffer over-read. This vulnerability has a CVSS score of 5.0, indicating a medium severity, and can be exploited remotely with low attack complexity, leading to a denial of service. There is no evidence of active exploitation, publicly available exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
2.0.1CPE matchmatch criteria
cpe:2.3:a:libexpat_project:libexpat:2.0.1:*:*:*:*:*:*:*
>= 2.0.35, < 2.0.64CPE matchmatch criteria
cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*
>= 2.2.0, < 2.2.17CPE matchmatch criteria
cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 2.0

5.0MEDIUM

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

Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Exploitability Score
10.0
Impact Score
2.9
CvssVersion
2.0

Exploit Intelligence

EPSS Score
27.92%
Probability of exploitation in next 30 days
EPSS Percentile
97.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.2792 is in the 98th percentile among its peer group of 23,701 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (11)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 3Fixed in: 4Suite-0:0.11.1-15
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 3Fixed in: expat-0:1.95.5-6.2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 4Fixed in: 4Suite-0:1.0-3.el4_8.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 4Fixed in: expat-0:1.95.7-4.el4_8.2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 4Fixed in: PyXML-0:0.8.3-6.el4_8.2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 4Fixed in: python-0:2.3.4-14.10.el4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: expat-0:1.95.8-8.3.el5_4.2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: PyXML-0:0.8.4-4.el5_4.2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: python-0:2.4.3-44.el5
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Enterprise Application Platform 6.4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 1.0
View patch

Vendor Advisories (1)

redhatCVE-2009-3720Moderate

expat: buffer over-read and crash on XML with malformed UTF-8 sequences

Jan 17, 2009

References

expat.cvs.sourceforge.net / viewvc/expat/expat/lib/xmltok_impl.c
Exploit
expat.cvs.sourceforge.net / viewvc/expat/expat/lib/xmltok_impl.c
Mailing ListThird Party Advisory
lists.fedoraproject.org / pipermail/package-announce/2010-November/051228.html
Third Party Advisory
lists.fedoraproject.org / pipermail/package-announce/2010-November/051247.html
Mailing ListThird Party Advisory
lists.fedoraproject.org / pipermail/package-announce/2010-November/051367.html
Third Party Advisory
lists.fedoraproject.org / pipermail/package-announce/2010-November/051405.html
Third Party Advisory
lists.fedoraproject.org / pipermail/package-announce/2010-November/051442.html
Third Party Advisory
lists.opensuse.org / opensuse-security-announce/2009-11/msg00004.html
Third Party Advisory
lists.opensuse.org / opensuse-security-announce/2010-05/msg00001.html
Third Party AdvisoryVDB Entry
lists.opensuse.org / opensuse-security-announce/2010-05/msg00002.html
Third Party AdvisoryVDB Entry
lists.opensuse.org / opensuse-security-announce/2010-06/msg00001.html
Third Party AdvisoryVDB Entry
lists.opensuse.org / opensuse-security-announce/2010-08/msg00001.html
Third Party AdvisoryVDB Entry
lists.vmware.com / pipermail/security-announce/2010/000082.html
Broken Link
mail.python.org / pipermail/expat-bugs/2009-January/002781.html
Third Party Advisory
marc.info
Mailing ListThird Party Advisory
bugs.gentoo.org / show_bug.cgi
Third Party Advisory
bugzilla.redhat.com / show_bug.cgi
Issue Tracking
secunia.com / advisories/37324
Broken Link
secunia.com / advisories/37537
Broken Link
secunia.com / advisories/37925
Broken Link
secunia.com / advisories/38050
Broken Link
secunia.com / advisories/38231
Broken Link
secunia.com / advisories/38794
Broken Link
secunia.com / advisories/38832
Broken Link
secunia.com / advisories/38834
Broken Link
secunia.com / advisories/39478
Broken Link
secunia.com / advisories/41701
Broken Link
secunia.com / advisories/42326
Broken Link
secunia.com / advisories/42338
Broken Link
secunia.com / advisories/43300
Broken Link
slackware.com / security/viewer.php
Mailing ListThird Party Advisory
lists.apache.org / thread.html/54a42d4b01968df1117cea77fc53d6beb931c0e05936ad02af93e9ac%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/5df9bfb86a3b054bb985a45ff9250b0332c9ecc181eec232489e7f79%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/8d63cb8e9100f28a99429b4328e4e7cebce861d5772ac9863ba2ae6f%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/f7f95ac1cd9895db2714fa3ebaa0b94d0c6df360f742a40951384a53%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/r0276683d8e1e07153fc8642618830ac0ade85b9ae0dc7b07f63bb8fc%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/r2295080a257bad27ea68ca0af12fc715577f9e84801eae116a33107e%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/r2cb985de917e7da0848c440535f65a247754db8b2154a10089e4247b%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/r476d175be0aaf4a17680ef98c5153b4d336eaef76fb2224cc94c463a%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/r57608dc51b79102f3952ae06f54d5277b649c86d6533dcd6a7d201f7%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/r5f9c22f9c28adbd9f00556059edc7b03a5d5bb71d4bb80257c0d34e4%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/r75cbe9ea3e2114e4271bbeca7aff96117b50c1b6eb7c4772b0337c1f%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/r8828e649175df56f1f9e3919938ac7826128525426e2748f0ab62feb%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/r9e8622254184645bc963a1d47c5d47f6d5a36d6f080d8d2c43b2b142%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/r9ea3538f229874c80a10af473856a81fbf5f694cd7f471cc679ba70b%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/r9f93cf6dde308d42a9c807784e8102600d0397f5f834890708bf6920%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/rad01d817195e6cc871cb1d73b207ca326379a20a6e7f30febaf56d24%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/rad2acee3ab838b52c04a0698b1728a9a43467bf365bd481c993c535d%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/rb9c9f42dafa25d2f669dac2a536a03f2575bc5ec1be6f480618aee10%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/rdca61ae990660bacb682295f2a09d34612b7bb5f457577fe17f4d064%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/reb7c64aeea604bf948467d9d1cab8ff23fa7d002be1964bcc275aae7%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/rf6449464fd8b7437704c55f88361b66f12d5b5f90bcce66af4be4ba9%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
lists.apache.org / thread.html/rfbaf647d52c1cb843e726a0933f156366a806cead84fbd430951591b%40%3Ccvs.httpd.apache.org%3E
Third Party Advisory
sourceforge.net / tracker/index.php
Mailing ListThird Party Advisory
oval.cisecurity.org / repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11019
Broken Link
oval.cisecurity.org / repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12719
Broken Link
oval.cisecurity.org / repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A7112
Mailing ListThird Party Advisory
sunsolve.sun.com / search/document.do
Broken Link
svn.python.org / view
Permissions RequiredThird Party Advisory
redhat.com / archives/fedora-package-announce/2009-December/msg00370.html
Third Party Advisory
redhat.com / archives/fedora-package-announce/2009-December/msg00413.html
Third Party Advisory
redhat.com / archives/fedora-package-announce/2009-December/msg01274.html
Third Party Advisory
mandriva.com / security/advisories
Permissions RequiredThird Party Advisory
mandriva.com / security/advisories
Broken Link
mandriva.com / security/advisories
Broken Link
mandriva.com / security/advisories
Broken Link
mandriva.com / security/advisories
Broken Link
mandriva.com / security/advisories
Broken Link
mandriva.com / security/advisories
Broken Link
mandriva.com / security/advisories
Broken Link
openwall.com / lists/oss-security/2009/08/21/2
Mailing List
openwall.com / lists/oss-security/2009/08/26/3
Mailing List
openwall.com / lists/oss-security/2009/08/26/4
Mailing List
openwall.com / lists/oss-security/2009/08/27/6
Mailing List
openwall.com / lists/oss-security/2009/09/06/1
Mailing List
openwall.com / lists/oss-security/2009/10/22/5
Mailing List
openwall.com / lists/oss-security/2009/10/22/9
Mailing List
openwall.com / lists/oss-security/2009/10/23/2
Mailing List
openwall.com / lists/oss-security/2009/10/23/6
Mailing List
openwall.com / lists/oss-security/2009/10/26/3
Mailing List
openwall.com / lists/oss-security/2009/10/28/3
Mailing List
redhat.com / support/errata/RHSA-2010-0002.html
Broken Link
redhat.com / support/errata/RHSA-2011-0896.html
Broken Link
securitytracker.com / id
Third Party AdvisoryVDB Entry
ubuntu.com / usn/USN-890-1
Third Party Advisory
ubuntu.com / usn/USN-890-6
Third Party Advisory
vupen.com / english/advisories/2010/0528
Broken Link
vupen.com / english/advisories/2010/0896
Broken Link
vupen.com / english/advisories/2010/1107
Broken Link
vupen.com / english/advisories/2010/3035
Broken Link
vupen.com / english/advisories/2010/3053
Broken Link
vupen.com / english/advisories/2010/3061
Broken Link
vupen.com / english/advisories/2011/0359
Broken Link