diff --git a/actionpack/lib/action_dispatch/middleware/cookies.rb b/actionpack/lib/action_dispatch/middleware/cookies.rb
index 2c0c31de9d..de9c55d96c 100644
--- a/actionpack/lib/action_dispatch/middleware/cookies.rb
+++ b/actionpack/lib/action_dispatch/middleware/cookies.rb
@@ -2,7 +2,7 @@ require 'active_support/core_ext/object/blank'
 require 'active_support/core_ext/hash/keys'
 
 module ActionDispatch
-  class Request
+  class Request < Rack::Request
     def cookie_jar
       env['action_dispatch.cookies'] ||= Cookies::CookieJar.build(self)
     end
diff --git a/actionpack/lib/action_dispatch/middleware/flash.rb b/actionpack/lib/action_dispatch/middleware/flash.rb
index bc68615be7..17776c2356 100644
--- a/actionpack/lib/action_dispatch/middleware/flash.rb
+++ b/actionpack/lib/action_dispatch/middleware/flash.rb
@@ -1,5 +1,5 @@
 module ActionDispatch
-  class Request
+  class Request < Rack::Request
     # Access the contents of the flash. Use <tt>flash["notice"]</tt> to
     # read a notice you put there or <tt>flash["notice"] = "hello"</tt>
     # to put a new one.