Index: wp-includes/shortcodes.php
===================================================================
--- wp-includes/shortcodes.php	(revision 18160)
+++ wp-includes/shortcodes.php	(working copy)
@@ -176,7 +176,7 @@
 	$tagregexp = join( '|', array_map('preg_quote', $tagnames) );
 
 	// WARNING! Do not change this regex without changing do_shortcode_tag() and strip_shortcodes()
-	return '(.?)\[('.$tagregexp.')\b(.*?)(?:(\/))?\](?:(.+?)\[\/\2\])?(.?)';
+	return '(.?)\[('.$tagregexp.')(?![\w-])(.*?)(?:(\/))?\](?:(.+?)\[\/\2\])?(.?)';
 }
 
 /**