Index: activesupport/test/json/decoding_test.rb
===================================================================
--- activesupport/test/json/decoding_test.rb	(revision 9250)
+++ activesupport/test/json/decoding_test.rb	(working copy)
@@ -24,7 +24,8 @@
     %(null)  => nil,
     %(true)  => true,
     %(false) => false,
-    %q("http:\/\/test.host\/posts\/1") => "http://test.host/posts/1"
+    %q({"bad":"\\\\","trailing":""}) => {"bad" => "\\", "trailing" => ""},
+    %q("http:\/\/test.host\/posts\/1") => "http://test.host/posts/1"
   }
   
   TESTS.each do |json, expected|
Index: activesupport/lib/active_support/json/decoding.rb
===================================================================
--- activesupport/lib/active_support/json/decoding.rb	(revision 9250)
+++ activesupport/lib/active_support/json/decoding.rb	(working copy)
@@ -38,7 +38,9 @@
                 quoting = false
               end
             when ":",","
-              marks << scanner.pos - 1 unless quoting
+              marks << scanner.pos - 1 unless quoting
+            when "\\"
+              scanner.skip(/\\/)
             end
           end