diff --git a/activesupport/lib/active_support/buffered_logger.rb b/activesupport/lib/active_support/buffered_logger.rb
index 33bcf327f8..9bf63a90b1 100644
--- a/activesupport/lib/active_support/buffered_logger.rb
+++ b/activesupport/lib/active_support/buffered_logger.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/class/attribute_accessors'
+
 module ActiveSupport
   # Inspired by the buffered logger idea by Ezra
   class BufferedLogger