diff --git a/actionpack/lib/action_dispatch/middleware/exception_wrapper.rb b/actionpack/lib/action_dispatch/middleware/exception_wrapper.rb
index 5595a73887..d176a73633 100644
--- a/actionpack/lib/action_dispatch/middleware/exception_wrapper.rb
+++ b/actionpack/lib/action_dispatch/middleware/exception_wrapper.rb
@@ -1,5 +1,6 @@
 require 'action_controller/metal/exceptions'
 require 'active_support/core_ext/module/attribute_accessors'
+require 'rack/utils'
 
 module ActionDispatch
   class ExceptionWrapper