actionpack/lib/action_dispatch/http/request.rb in Ruby on Rails before 3.0.14, 3.1.x before 3.1.6, and 3.2.x before 3.2.6 does not properly consider differences in parameter handling between the Active Record component and the Rack interface, which allows remote attackers to bypass intended database-query restrictions and perform NULL checks via a crafted request, as demonstrated by certain "['xyz', nil]" values, a related issue to CVE-2012-2660.

The session fixation protection mechanism in cgi_process.rb in Rails 1.2.4, as used in Ruby on Rails, removes the :cookie_only attribute from the DEFAULT_SESSION_OPTIONS constant, which effectively causes cookie_only to be applied only to the first instantiation of CgiRequest, which allows remote attackers to conduct session fixation attacks. NOTE: this is due to an incomplete fix for CVE-2007-5380.