CVE-2009-1955

Exp

The expat XML parser in the apr_xml_* interface in xml/apr_xml.c in Apache APR-util before 1.3.7, as used in the mod_dav and mod_dav_svn modules in the Apache HTTP Server, allows remote attackers to cause a denial of service (memory consumption) via a crafted XML document containing a large number of nested entity references, as demonstrated by a PROPFIND request, a similar issue to CVE-2003-1564.

Published: 2009-06-07 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2009-1955 is rated High Exploit Risk (79.3/100): CVSS High severity, with high exploitation likelihood (EPSS 52.99%, 99th percentile). 2 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2009-1955

EDB-ID Source Kind Published Link
8842 exploit_db edb 2009-06-01 Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2009-1955

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-26 53.27% 52.99% -0.28%
2 2026-06-15 2.01% 53.27% +51.26%
3 2026-06-13 — 2.01% —

Full EPSS history (33 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2009-1955

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2009-1955

OS Trackers for CVE-2009-1955

vendor priority summary link
debian medium CVE-2009-1955 medium priority: Debian including 1 source packages (apr-util), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2009-1955
gentoo normal CVE-2009-1955: 1 GLSA(s) (200907-03), 1 atom(s) (dev-libs/apr-util); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2009-1955
redhat medium — https://access.redhat.com/security/cve/CVE-2009-1955
suse high CVE-2009-1955 severity important: SUSE including 78 source package names (apache2-2.4.10-6.1, apache2-2.4.16-5.1, …), 100 product×package rows across 22 product lines (SUSE Linux Enterprise High Performance Computing 12 SP5, SUSE Linux Enterprise Module for Server Applications 15, … (22 product lines)): Fixed 100. https://www.suse.com/security/cve/CVE-2009-1955/
ubuntu medium CVE-2009-1955 medium priority: Ubuntu including 2 source packages (apache2, apr-util), 10 status rows across 5 suites (dapper, hardy, intrepid, jaunty, upstream): released 5, not-affected 3, DNE 1, needs-triage 1. https://ubuntu.com/security/CVE-2009-1955

Affected software / configurations for CVE-2009-1955

Vendor Product Version Raw CPE
apache apr-util < 1.3.7 cpe:2.3:a:apache:apr-util:*:*:*:*:*:*:*:*
apple mac_os_x < 10.6.2 cpe:2.3:o:apple:mac_os_x:*:*:*:*:*:*:*:*
suse linux_enterprise_server 9 cpe:2.3:o:suse:linux_enterprise_server:9:*:*:*:*:*:*:*
debian debian_linux 4.0 cpe:2.3:o:debian:debian_linux:4.0:*:*:*:*:*:*:*
canonical ubuntu_linux 6.06 cpe:2.3:o:canonical:ubuntu_linux:6.06:*:*:*:*:*:*:*
canonical ubuntu_linux 8.04 cpe:2.3:o:canonical:ubuntu_linux:8.04:*:*:*:-:*:*:*
canonical ubuntu_linux 8.10 cpe:2.3:o:canonical:ubuntu_linux:8.10:*:*:*:*:*:*:*
canonical ubuntu_linux 9.04 cpe:2.3:o:canonical:ubuntu_linux:9.04:*:*:*:*:*:*:*
fedoraproject fedora 9 cpe:2.3:o:fedoraproject:fedora:9:*:*:*:*:*:*:*
fedoraproject fedora 10 cpe:2.3:o:fedoraproject:fedora:10:*:*:*:*:*:*:*
fedoraproject fedora 11 cpe:2.3:o:fedoraproject:fedora:11:*:*:*:*:*:*:*
oracle http_server — cpe:2.3:a:oracle:http_server:-:*:*:*:*:*:*:*
apache http_server >= 2.2.0, < 2.2.12 cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*

References for CVE-2009-1955

URL Tags
http://lists.apple.com/archives/security-announce/2009/Nov/msg00000.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2010-05/msg00001.html Mailing List Third Party Advisory
http://marc.info/?l=apr-dev&m=124396021826125&w=2 Mailing List Patch
http://marc.info/?l=bugtraq&m=129190899612998&w=2 Mailing List
http://secunia.com/advisories/34724 Broken Link Third Party Advisory
http://secunia.com/advisories/35284 Broken Link Third Party Advisory
http://secunia.com/advisories/35360 Broken Link Third Party Advisory
http://secunia.com/advisories/35395 Broken Link Third Party Advisory
http://secunia.com/advisories/35444 Broken Link Third Party Advisory
http://secunia.com/advisories/35487 Broken Link Third Party Advisory
http://secunia.com/advisories/35565 Broken Link Third Party Advisory
http://secunia.com/advisories/35710 Broken Link Third Party Advisory
http://secunia.com/advisories/35797 Broken Link Third Party Advisory
http://secunia.com/advisories/35843 Broken Link Third Party Advisory
http://secunia.com/advisories/36473 Broken Link Third Party Advisory
http://secunia.com/advisories/37221 Broken Link Third Party Advisory
http://security.gentoo.org/glsa/glsa-200907-03.xml Third Party Advisory
http://slackware.com/security/viewer.php?l=slackware-security&y=2009&m=slackware-security.538210 Broken Link Third Party Advisory
http://support.apple.com/kb/HT3937 Broken Link
http://svn.apache.org/viewvc?view=rev&revision=781403 Patch
http://wiki.rpath.com/Advisories:rPSA-2009-0123 Broken Link
http://www-01.ibm.com/support/docview.wss?uid=swg1PK88342 Broken Link
http://www-01.ibm.com/support/docview.wss?uid=swg1PK91241 Broken Link Third Party Advisory
http://www-01.ibm.com/support/docview.wss?uid=swg1PK99478 Broken Link Third Party Advisory
http://www-01.ibm.com/support/docview.wss?uid=swg27014463 Broken Link Third Party Advisory
http://www.apache.org/dist/apr/CHANGES-APR-UTIL-1.3 Broken Link
http://www.debian.org/security/2009/dsa-1812 Mailing List Third Party Advisory
http://www.mandriva.com/security/advisories?name=MDVSA-2009:131 Broken Link Third Party Advisory
http://www.mandriva.com/security/advisories?name=MDVSA-2013:150 Broken Link Third Party Advisory
http://www.openwall.com/lists/oss-security/2009/06/03/4 Mailing List
http://www.oracle.com/technetwork/topics/security/cpuapr2013-1899555.html Patch Third Party Advisory
http://www.redhat.com/support/errata/RHSA-2009-1107.html Broken Link Third Party Advisory
http://www.redhat.com/support/errata/RHSA-2009-1108.html Broken Link Third Party Advisory
http://www.securityfocus.com/archive/1/506053/100/0/threaded Broken Link Third Party Advisory VDB Entry
http://www.securityfocus.com/bid/35253 Broken Link Third Party Advisory VDB Entry
http://www.ubuntu.com/usn/usn-786-1 Third Party Advisory
http://www.ubuntu.com/usn/usn-787-1 Third Party Advisory
http://www.vupen.com/english/advisories/2009/1907 Broken Link Third Party Advisory
http://www.vupen.com/english/advisories/2009/3184 Broken Link Third Party Advisory
http://www.vupen.com/english/advisories/2010/1107 Broken Link Third Party Advisory
https://lists.apache.org/thread.html/8d63cb8e9100f28a99429b4328e4e7cebce861d5772ac9863ba2ae6f%40%3Ccvs.httpd.apache.org%3E Mailing List Patch
https://lists.apache.org/thread.html/f7f95ac1cd9895db2714fa3ebaa0b94d0c6df360f742a40951384a53%40%3Ccvs.httpd.apache.org%3E Mailing List Patch
https://lists.apache.org/thread.html/r2295080a257bad27ea68ca0af12fc715577f9e84801eae116a33107e%40%3Ccvs.httpd.apache.org%3E Mailing List Patch
https://lists.apache.org/thread.html/r476d175be0aaf4a17680ef98c5153b4d336eaef76fb2224cc94c463a%40%3Ccvs.httpd.apache.org%3E Mailing List Patch
https://lists.apache.org/thread.html/r57608dc51b79102f3952ae06f54d5277b649c86d6533dcd6a7d201f7%40%3Ccvs.httpd.apache.org%3E Mailing List Patch
https://lists.apache.org/thread.html/r75cbe9ea3e2114e4271bbeca7aff96117b50c1b6eb7c4772b0337c1f%40%3Ccvs.httpd.apache.org%3E Mailing List Patch
https://lists.apache.org/thread.html/r9ea3538f229874c80a10af473856a81fbf5f694cd7f471cc679ba70b%40%3Ccvs.httpd.apache.org%3E Mailing List Patch
https://lists.apache.org/thread.html/r9f93cf6dde308d42a9c807784e8102600d0397f5f834890708bf6920%40%3Ccvs.httpd.apache.org%3E Mailing List Patch
https://lists.apache.org/thread.html/rad01d817195e6cc871cb1d73b207ca326379a20a6e7f30febaf56d24%40%3Ccvs.httpd.apache.org%3E Mailing List Patch
https://lists.apache.org/thread.html/rc4c53a0d57b2771ecd4b965010580db355e38137c8711311ee1073a8%40%3Ccvs.httpd.apache.org%3E Mailing List Patch
https://lists.apache.org/thread.html/rdca61ae990660bacb682295f2a09d34612b7bb5f457577fe17f4d064%40%3Ccvs.httpd.apache.org%3E Mailing List Patch
https://lists.apache.org/thread.html/reb7c64aeea604bf948467d9d1cab8ff23fa7d002be1964bcc275aae7%40%3Ccvs.httpd.apache.org%3E Mailing List Patch
https://lists.apache.org/thread.html/rf6449464fd8b7437704c55f88361b66f12d5b5f90bcce66af4be4ba9%40%3Ccvs.httpd.apache.org%3E Mailing List Patch
https://lists.apache.org/thread.html/rfbaf647d52c1cb843e726a0933f156366a806cead84fbd430951591b%40%3Ccvs.httpd.apache.org%3E Mailing List Patch
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10270 Broken Link Third Party Advisory
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12473 Broken Link Third Party Advisory
https://www.exploit-db.com/exploits/8842 Exploit VDB Entry
https://www.redhat.com/archives/fedora-package-announce/2009-June/msg01173.html Mailing List
https://www.redhat.com/archives/fedora-package-announce/2009-June/msg01201.html Mailing List
https://www.redhat.com/archives/fedora-package-announce/2009-June/msg01228.html Mailing List
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