Multiple directory traversal vulnerabilities in server.rb in Sprockets before 2.0.5, 2.1.x before 2.1.4, 2.2.x before 2.2.3, 2.3.x before 2.3.3, 2.4.x before 2.4.6, 2.5.x before 2.5.1, 2.6.x and 2.7.x before 2.7.1, 2.8.x before 2.8.3, 2.9.x before 2.9.4, 2.10.x before 2.10.2, 2.11.x before 2.11.3, 2.12.x before 2.12.3, and 3.x before 3.0.0.beta.3, as distributed with Ruby on Rails 3.x and 4.x, allow remote attackers to determine the existence of files outside the application root via a ../ (dot dot slash) sequence with (1) double slashes or (2) URL encoding.
https://groups.google.com/forum/message/raw?msg=rubyonrails-security/wQBeGXqGs3E/JqUMB6fhh3gJ
https://groups.google.com/forum/message/raw?msg=rubyonrails-security/doAVp0YaTqY/aHFngBqNBoAJ
http://lists.opensuse.org/opensuse-updates/2014-11/msg00111.html
http://lists.opensuse.org/opensuse-updates/2014-11/msg00110.html
http://lists.opensuse.org/opensuse-updates/2014-11/msg00105.html
http://lists.opensuse.org/opensuse-updates/2014-11/msg00103.html