diff --git a/lib/cgi.rb b/lib/cgi.rb
new file mode 100644
index 0000000000..71b52b6267
--- /dev/null
+++ b/lib/cgi.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+require "cgi/escape"
+warn <<-WARNING, uplevel: 1 if $VERBOSE
+CGI library is removed from Ruby 3.5. Please use cgi/escape instead for CGI.escape and CGI.unescape features.
+If you need to use the full features of CGI library, Please install cgi gem.
+WARNING
diff --git a/lib/cgi/util.rb b/lib/cgi/util.rb
new file mode 100644
index 0000000000..b862341e90
--- /dev/null
+++ b/lib/cgi/util.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+require "cgi/escape"
+warn <<-WARNING, uplevel: 1 if $VERBOSE
+CGI::Util is removed from Ruby 3.5. Please use cgi/escape instead for CGI.escape and CGI.unescape features.
+WARNING