diff --git a/ChangeLog b/ChangeLog
index 10e7f03566..3e0cf04eb3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sat Jul 29 06:12:06 2006  Hidetoshi NAGAI  <nagai@ai.kyutech.ac.jp>
+
+	* ext/tk/lib/multi-tk.rb: freeze ip_name for security reason.
+
 Fri Jul 28 17:18:03 2006  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* ext/curses/curses.c (NUM2CH, CH2FIX): use single char strings.
diff --git a/ext/tk/lib/multi-tk.rb b/ext/tk/lib/multi-tk.rb
index 36cb4388ae..78ed1aa6ee 100644
--- a/ext/tk/lib/multi-tk.rb
+++ b/ext/tk/lib/multi-tk.rb
@@ -949,7 +949,7 @@ class MultiTkIp
   def _create_slave_ip_name
     name = @@SLAVE_IP_ID.join('')
     @@SLAVE_IP_ID[1].succ!
-    name
+    name.freeze
   end
   private :_create_slave_ip_name