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 mod
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
- Jun 7, 2009
- Updated
- Jun 16, 2026
- EPSS
- 53.0% · 99th percentile
- CWE
- CWE-776
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
46
Plan
Add it to your regular patch cycle.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 16 / 30 · 53.0%
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| apache | apr-util | cpe:2.3:a:apache:apr-util |
| apache | http server | cpe:2.3:a:apache:http_server |
| apple | mac os x | cpe:2.3:o:apple:mac_os_x |
| suse | linux enterprise server | cpe:2.3:o:suse:linux_enterprise_server |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| canonical | ubuntu linux | cpe:2.3:o:canonical:ubuntu_linux |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| oracle | http server | cpe:2.3:a:oracle:http_server |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- apache http server2.2.0 and later · before 2.2.12
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | apr-util | before 1.3.7+dfsg-1 | 1.3.7+dfsg-1 |
| Debian:4.0 | apr-util | before 1.2.7+dfsg-2+etch2 | 1.2.7+dfsg-2+etch2 |
| Debian:5.0 | apr-util | before 1.2.12+dfsg-8+lenny2 | 1.2.12+dfsg-8+lenny2 |
| openSUSE:Tumbleweed | apache2 | before 2.4.23-4.1 | 2.4.23-4.1 |
| Red Hat:enterprise_linux:3::as | httpd | before 0:2.0.46-73.ent | 0:2.0.46-73.ent |
| Red Hat:enterprise_linux:3::as | httpd-debuginfo | before 0:2.0.46-73.ent | 0:2.0.46-73.ent |
| Red Hat:enterprise_linux:3::as | httpd-devel | before 0:2.0.46-73.ent | 0:2.0.46-73.ent |
| Red Hat:enterprise_linux:3::as | mod_ssl | before 1:2.0.46-73.ent | 1:2.0.46-73.ent |
| Red Hat:enterprise_linux:4::as | apr-util | before 0:0.9.4-22.el4_8.1 | 0:0.9.4-22.el4_8.1 |
| Red Hat:enterprise_linux:4::as | apr-util-debuginfo | before 0:0.9.4-22.el4_8.1 | 0:0.9.4-22.el4_8.1 |
| Red Hat:enterprise_linux:4::as | apr-util-devel | before 0:0.9.4-22.el4_8.1 | 0:0.9.4-22.el4_8.1 |
| Red Hat:enterprise_linux:5::client | apr-util-docs | before 0:1.2.7-7.el5_3.1 | 0:1.2.7-7.el5_3.1 |
| Red Hat:enterprise_linux:5::client_workstation | apr-util | before 0:1.2.7-7.el5_3.1 | 0:1.2.7-7.el5_3.1 |
| Red Hat:enterprise_linux:5::client_workstation | apr-util-debuginfo | before 0:1.2.7-7.el5_3.1 | 0:1.2.7-7.el5_3.1 |
| Red Hat:enterprise_linux:5::client_workstation | apr-util-devel | before 0:1.2.7-7.el5_3.1 | 0:1.2.7-7.el5_3.1 |
| Red Hat:jboss_enterprise_web_server:1::el4 | httpd22 | before 0:2.2.10-23.1.ep5.el4 | 0:2.2.10-23.1.ep5.el4 |
| Red Hat:jboss_enterprise_web_server:1::el4 | httpd22-apr | before 0:2.2.10-23.1.ep5.el4 | 0:2.2.10-23.1.ep5.el4 |
| Red Hat:jboss_enterprise_web_server:1::el4 | httpd22-apr-devel | before 0:2.2.10-23.1.ep5.el4 | 0:2.2.10-23.1.ep5.el4 |
| Red Hat:jboss_enterprise_web_server:1::el4 | httpd22-apr-util | before 0:2.2.10-23.1.ep5.el4 | 0:2.2.10-23.1.ep5.el4 |
| Red Hat:jboss_enterprise_web_server:1::el4 | httpd22-apr-util-devel | before 0:2.2.10-23.1.ep5.el4 | 0:2.2.10-23.1.ep5.el4 |
| Red Hat:jboss_enterprise_web_server:1::el4 | httpd22-debuginfo | before 0:2.2.10-23.1.ep5.el4 | 0:2.2.10-23.1.ep5.el4 |
| Red Hat:jboss_enterprise_web_server:1::el4 | httpd22-devel | before 0:2.2.10-23.1.ep5.el4 | 0:2.2.10-23.1.ep5.el4 |
| Red Hat:jboss_enterprise_web_server:1::el4 | mod_ssl22 | before 1:2.2.10-23.1.ep5.el4 | 1:2.2.10-23.1.ep5.el4 |
Same product
apache: all recordsOther highest-scoring records for the same primary product.
- CVE-2009-2412Multiple integer overflows in the Apache Portable Runtime (APR) library and the Apache Portable Utility library (aka APR-util) 0.9.x and 1.344Plan
- CVE-2026-34191Apache Portable Runtime Utility: SQL Injection in apr_dbd_oracle36Monitor
- CVE-2026-32327Apache Portable Runtime Utility: apr-util XML stack recursion crash36Monitor
- CVE-2025-49506Apache Portable Runtime Utility: apr_password_validate() vulnerable to timing attack30Monitor
- CVE-2026-34502Apache Portable Runtime Utility: Heap buffer overflow in APR memcached client30Monitor
- CVE-2026-34501Apache Portable Runtime Utility: Heap buffer overflow in APR redis client30Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:apr-util | 1.3.7+dfsg-1 · Debian:12 | Package registry (OSV) |
| opensuse:apache2 | 2.4.23-4.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| red hat:apr-util | 0:0.9.4-22.el4_8.1 · Red Hat:enterprise_linux:4::as | Package registry (OSV) |
| red hat:apr-util-debuginfo | 0:0.9.4-22.el4_8.1 · Red Hat:enterprise_linux:4::as | Package registry (OSV) |
| red hat:apr-util-devel | 0:0.9.4-22.el4_8.1 · Red Hat:enterprise_linux:4::as | Package registry (OSV) |
| red hat:apr-util-docs | 0:1.2.7-7.el5_3.1 · Red Hat:enterprise_linux:5::client | Package registry (OSV) |
| red hat:httpd | 0:2.0.46-73.ent · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
| red hat:httpd-debuginfo | 0:2.0.46-73.ent · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
| red hat:httpd-devel | 0:2.0.46-73.ent · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
| red hat:httpd22 | 0:2.2.10-23.1.ep5.el4 · Red Hat:jboss_enterprise_web_server:1::el4 | Package registry (OSV) |
| red hat:httpd22-apr | 0:2.2.10-23.1.ep5.el4 · Red Hat:jboss_enterprise_web_server:1::el4 | Package registry (OSV) |
| red hat:httpd22-apr-devel | 0:2.2.10-23.1.ep5.el4 · Red Hat:jboss_enterprise_web_server:1::el4 | Package registry (OSV) |
| red hat:httpd22-apr-util | 0:2.2.10-23.1.ep5.el4 · Red Hat:jboss_enterprise_web_server:1::el4 | Package registry (OSV) |
| red hat:mod_ssl | 1:2.0.46-73.ent · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
Exploit status
Proof of concept available
A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.
Evidence
- Exploit-DB entry ×1
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Exploit-DB entry | dos | 2009-06-01 |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- First PoC-7 d
- Published
- TodayOct 10, 2026+6334 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-776 · Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- lists.apple.com/archives/security-announce/2009/Nov/msg00000.html
- lists.opensuse.org/opensuse-security-announce/2010-05/msg00001.html
- marc.info/?l=apr-dev&m=124396021826125&w=2
- marc.info/?l=bugtraq&m=129190899612998&w=2
- secunia.com/advisories/34724
- secunia.com/advisories/35284
- secunia.com/advisories/35360
- secunia.com/advisories/35395
- secunia.com/advisories/35444
- secunia.com/advisories/35487
- secunia.com/advisories/35565
- secunia.com/advisories/35710
- secunia.com/advisories/35797
- secunia.com/advisories/35843
- secunia.com/advisories/36473
- secunia.com/advisories/37221
- security.gentoo.org/glsa/glsa-200907-03.xml
- slackware.com/security/viewer.php?l=slackware-security&y=2009&m=slackware-security.538210
- support.apple.com/kb/HT3937
- svn.apache.org/viewvc?view=rev&revision=781403
Vendor advisories and official records. Exploit/PoC links are deliberately left out.