There is an information leak vulnerability in Sprockets. Versions Affected: 4.0.0.beta7 and lower, 3.7.1 and lower, 2.12.4 and lower. Specially crafted requests can be used to access files that exists on the filesystem that is outside an application's root directory, when the Sprockets server is used in production. All users running an affected release should either upgrade or use one of the work arounds immediately.

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.