diff --git a/activerecord/lib/active_record/attribute_assignment.rb b/activerecord/lib/active_record/attribute_assignment.rb
index e536f5ebcc67581f151636bccba1b6f66fc9792b..a13bb9299aa72f3e95b115789d1d30a1e9ee1eb6 100644
--- a/activerecord/lib/active_record/attribute_assignment.rb
+++ b/activerecord/lib/active_record/attribute_assignment.rb
@@ -1,3 +1,4 @@
+require 'active_model/forbidden_attributes_protection'
 
 module ActiveRecord
   module AttributeAssignment