diff --git a/lib/rexml/parsers/baseparser.rb b/lib/rexml/parsers/baseparser.rb
index 44dc6580..28810bfa 100644
--- a/lib/rexml/parsers/baseparser.rb
+++ b/lib/rexml/parsers/baseparser.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 require_relative '../parseexception'
 require_relative '../undefinednamespaceexception'
+require_relative '../security'
 require_relative '../source'
 require 'set'
 require "strscan"