Ruby on Rails 2.1.x, 2.2.x, and 2.3.x before 2.3.11, and 3.x before 3.0.4, does not properly validate HTTP requests that contain an X-Requested-With header, which makes it easier for remote attackers to conduct cross-site request forgery (CSRF) attacks via forged (1) AJAX or (2) API requests that leverage "combinations of browser plugins and HTTP redirects," a related issue to CVE-2011-0696.
http://www.vupen.com/english/advisories/2011/0877
http://www.vupen.com/english/advisories/2011/0587
http://www.securitytracker.com/id?1025060
http://www.securityfocus.com/bid/46291
http://www.debian.org/security/2011/dsa-2247
http://weblog.rubyonrails.org/2011/2/8/csrf-protection-bypass-in-ruby-on-rails
http://secunia.com/advisories/43666
http://secunia.com/advisories/43274
http://lists.fedoraproject.org/pipermail/package-announce/2011-March/055088.html
http://lists.fedoraproject.org/pipermail/package-announce/2011-March/055074.html
http://lists.fedoraproject.org/pipermail/package-announce/2011-April/057650.html
http://groups.google.com/group/rubyonrails-security/msg/c22ea1668c0d181c?dmode=source&output=gplain