diff --git a/ChangeLog b/ChangeLog
index 60404ec3bb..a7793b5644 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,7 +1,7 @@
 Thu Nov 29 22:23:31 2012  Hiroshi Nakamura  <nahi@ruby-lang.org>
 
 	* test/openssl/test_cipher.rb (test_ctr_if_exists): add CTR mode test
-  	  if underlying OpenSSL supports it.
+  	  if underlying OpenSSL supports it. See #4408
 
 Thu Nov 29 21:42:16 2012  Shugo Maeda  <shugo@ruby-lang.org>