Ruby on Rails Improper Limitation of a Pathname to a Restricted Directory (Path Traversal) Vulnerability - CVE-2014-7818
Directory traversal vulnerability in actionpack/lib/action_dispatch/middleware/static.rb in Action Pack in Ruby on Rails 3.x before 3.2.20 4.0.x before 4.0.11 4.1.x before 4.1.7 and 4.2.x before 4.2.0.beta3 when serve_static_assets is enabled allows remote attackers to determine the existence of files outside the application root via a /..2F sequence.