Index: wp-includes/shortcodes.php
===================================================================
--- wp-includes/shortcodes.php	(revision 10684)
+++ wp-includes/shortcodes.php	(working copy)
@@ -175,7 +175,7 @@
 	$tagnames = array_keys($shortcode_tags);
 	$tagregexp = join( '|', array_map('preg_quote', $tagnames) );
 
-	return '(.?)\[('.$tagregexp.')\b(.*?)(?:(\/))?\](?:(.+?)\[\/\2\])?(.?)';
+	return '(.?)\[('.$tagregexp.')\b(.*?)(?:(\/))?\](?(4)|(?:(.+?)\[\/\2\]))?(.?)';
 }
 
 /**
@@ -294,4 +294,4 @@
 
 add_filter('the_content', 'do_shortcode', 11); // AFTER wpautop()
 
-?>
\ No newline at end of file
+?>