diff --git a/ChangeLog b/ChangeLog
index 694794beb4..66b32ca3e8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Aug 19 11:28:58 2011  Shugo Maeda  <shugo@ruby-lang.org>
+
+	* lib/net/imap.rb (msg_att): accepts extra space before ')'.
+	  based on the patch by art lussos.  [Bug #5163] [ruby-core:38820]
+
 Wed Aug 17 23:01:00 2011  Kenta Murata  <mrkn@mrkn.jp>
 
 	* ext/bigdecimal/bigdecimal.c (cannot_be_coerced_into_BigDecimal):
diff --git a/lib/net/imap.rb b/lib/net/imap.rb
index 06e1a30094..9095ea399a 100644
--- a/lib/net/imap.rb
+++ b/lib/net/imap.rb
@@ -2170,7 +2170,7 @@ module Net
             break
           when T_SPACE
             shift_token
-            token = lookahead
+            next
           end
           case token.value
           when /\A(?:ENVELOPE)\z/ni
diff --git a/test/net/imap/test_imap_response_parser.rb b/test/net/imap/test_imap_response_parser.rb
index ccdffd21ca..6a5a117408 100644
--- a/test/net/imap/test_imap_response_parser.rb
+++ b/test/net/imap/test_imap_response_parser.rb
@@ -99,4 +99,21 @@ EOF
 EOF
     assert_equal [1, 2, 3], response.data
   end
+
+  def test_msg_att_extra_space
+    parser = Net::IMAP::ResponseParser.new
+    response = parser.parse(<<EOF.gsub(/\n/, "\r\n").taint)
+* 1 FETCH (UID 92285)
+EOF
+    assert_equal 92285, response.data.attr["UID"]
+
+    response = parser.parse(<<EOF.gsub(/\n/, "\r\n").taint)
+* 1 FETCH (UID 92285 )
+EOF
+    assert_equal 92285, response.data.attr["UID"]
+
+    response = parser.parse(<<EOF.gsub(/\n/, "\r\n").taint)
+* 1 FETCH (UID 92285  )
+EOF
+  end
 end