diff --git a/wp-admin/setup-config.php b/wp-admin/setup-config.php
index e32899d543..6d1e2972f5 100644
--- a/wp-admin/setup-config.php
+++ b/wp-admin/setup-config.php
@@ -85,7 +85,7 @@ function display_header() {
 <head>
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
 <title><?php _e( 'WordPress &rsaquo; Setup Configuration File' ); ?></title>
-<link rel="stylesheet" href="css/install.css?ver=<?php echo $wp_version; ?>" type="text/css" />
+<link rel="stylesheet" href="css/install.css?ver=<?php echo preg_replace( '/[^0-9a-z\.-]/i', '', $wp_version ); ?>" type="text/css" />
 
 </head>
 <body>
