The HTTP/XMLRPC server in Ruby before 1.8.2 uses blocking sockets, which allows attackers to cause a denial of service (blocked connections) via a large amount of data.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11100
https://exchange.xforce.ibmcloud.com/vulnerabilities/26102
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=189540
http://www.securityfocus.com/bid/17645
http://www.redhat.com/support/errata/RHSA-2006-0427.html
http://www.novell.com/linux/security/advisories/2006-06-02.html
http://www.mandriva.com/security/advisories?name=MDKSA-2006:079
http://www.gentoo.org/security/en/glsa/glsa-200605-11.xml
http://www.debian.org/security/2006/dsa-1157
http://securitytracker.com/id?1015978
http://secunia.com/advisories/21657
http://secunia.com/advisories/20457
http://secunia.com/advisories/20064
http://secunia.com/advisories/20024
http://secunia.com/advisories/19804
http://secunia.com/advisories/19772
http://secunia.com/advisories/16904
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-dev/27787