The REXML module in Ruby 1.8.6 through 1.8.6-p287, 1.8.7 through 1.8.7-p72, and 1.9 allows context-dependent attackers to cause a denial of service (CPU consumption) via an XML document with recursively nested entities, aka an “XML entity explosion.”
groups.google.com/group/comp.lang.ruby/browse_thread/thread/19f69e8a081fc0d1/e138e014b74352ca
lists.apple.com/archives/security-announce/2009/May/msg00002.html
secunia.com/advisories/31602
secunia.com/advisories/32165
secunia.com/advisories/32219
secunia.com/advisories/32255
secunia.com/advisories/32256
secunia.com/advisories/32371
secunia.com/advisories/33178
secunia.com/advisories/33185
secunia.com/advisories/35074
security.gentoo.org/glsa/glsa-200812-17.xml
support.apple.com/kb/HT3549
support.avaya.com/elmodocs2/security/ASA-2008-424.htm
weblog.rubyonrails.org/2008/9/3/rails-2-0-4-maintenance-release
www.debian.org/security/2008/dsa-1651
www.debian.org/security/2008/dsa-1652
www.openwall.com/lists/oss-security/2008/08/25/4
www.openwall.com/lists/oss-security/2008/08/26/1
www.openwall.com/lists/oss-security/2008/08/26/4
www.redhat.com/support/errata/RHSA-2008-0897.html
www.ruby-lang.org/en/news/2008/08/23/dos-vulnerability-in-rexml/
www.ruby-lang.org/security/20080823rexml/rexml-expansion-fix.rb
www.securityfocus.com/bid/30802
www.securitytracker.com/id?1020735
www.us-cert.gov/cas/techalerts/TA09-133A.html
www.vupen.com/english/advisories/2008/2428
www.vupen.com/english/advisories/2008/2483
www.vupen.com/english/advisories/2009/1297
exchange.xforce.ibmcloud.com/vulnerabilities/44628
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10393
usn.ubuntu.com/651-1/
usn.ubuntu.com/691-1/
www.redhat.com/archives/fedora-package-announce/2008-October/msg00259.html
www.redhat.com/archives/fedora-package-announce/2008-October/msg00299.html