What’s Vulnerable › Vulnerabilities

CVE-2009-1955

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 53.0% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2009-06-08 · updated 2026-06-16
• Weakness: CWE-776

Description

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.

Affected products

• Apache Apr-Util: before 1.3.7 — fixed in 1.3.7
• Apache HTTP Server: from 2.2.0 before 2.2.12 — fixed in 2.2.12
• macOS: before 10.6.2 — fixed in 10.6.2
• Canonical Ubuntu Linux: 6.06, 8.04, 8.10, 9.04
• Debian Linux: 4.0
• Fedoraproject Fedora: 9, 10, 11
• Oracle Corporation Oracle HTTP Server: all versions
• SUSE Linux Enterprise Server: 9

How to fix

Upgrade to a fixed version: Apache Apr-Util 1.3.7; Apache HTTP Server 2.2.12; macOS 10.6.2. Check the vendor advisory for mitigations.

References

• http://lists.apple.com/archives/security-announce/2009/Nov/msg00000.html
• http://lists.opensuse.org/opensuse-security-announce/2010-05/msg00001.html
• http://marc.info/?l=apr-dev&m=124396021826125&w=2
• http://marc.info/?l=bugtraq&m=129190899612998&w=2
• http://secunia.com/advisories/34724
• http://secunia.com/advisories/35284
• http://secunia.com/advisories/35360
• http://secunia.com/advisories/35395
• http://secunia.com/advisories/35444
• http://secunia.com/advisories/35487
• http://secunia.com/advisories/35565
• http://secunia.com/advisories/35710

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