CVE-2009-1955: Apache Apr-Util

High severity, CVSS 7.5. EPSS: 53% chance of exploitation in the next 30 days.

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)
• Apple Mac OS X: before 10.6.2 (fixed in 10.6.2)
• Canonical Ubuntu Linux: version 6.06 only; version 8.04 only; version 8.10 only; version 9.04 only
• Debian Debian Linux: version 4.0 only
• Fedoraproject Fedora: version 9 only; version 10 only; version 11 only
• Oracle HTTP Server: affected versions not specified
• Suse Linux Enterprise Server: version 9 only

Published 2009-06-08. Last modified 2026-06-16.