commit 099a98e9b7108dae3e0f78b207e0a7dc5913bd1a
Author: Michael Koziarski <michael@koziarski.com>
Date:   Sun Nov 16 20:35:25 2008 +0100

    Verify form submissions for text/plain posts too.
    
    Some browsers can POST requests with text/plain encoding, allowing attackers to  potentially subvert the request forgery prevention.
    
    http://pseudo-flaw.net/content/web-browsers/form-data-encoding-roundup/

diff --git a/actionpack/lib/action_controller/mime_type.rb b/actionpack/lib/action_controller/mime_type.rb
index fa123f7..453fc67 100644
--- a/actionpack/lib/action_controller/mime_type.rb
+++ b/actionpack/lib/action_controller/mime_type.rb
@@ -18,7 +18,7 @@ module Mime
   #   end
   class Type
     @@html_types = Set.new [:html, :all]
-    @@unverifiable_types = Set.new [:text, :json, :csv, :xml, :rss, :atom, :yaml]
+    @@unverifiable_types = Set.new [:json, :csv, :xml, :rss, :atom, :yaml]
     cattr_reader :html_types, :unverifiable_types
 
     # A simple helper class used in parsing the accept header