diff --git a/ChangeLog b/ChangeLog
index babe1db2ea..391d1436b8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Sep 29 10:58:07 2004  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* enum.c (sort_by_i): internally used object must not be changed
+	  outside.  [ruby-dev:24368]
+
 Mon Sep 27 21:25:12 2004  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* eval.c (rb_call0): invoke finalizers periodically.
diff --git a/enum.c b/enum.c
index d066af1c25..eee0e04291 100644
--- a/enum.c
+++ b/enum.c
@@ -393,6 +393,7 @@ sort_by_i(i, ary)
 
     v = rb_yield(i);
     e = rb_assoc_new(v, i);
+    OBJ_FREEZE(e);
     rb_ary_push(ary, e);
     return Qnil;
 }