diff --git a/wp-includes/pluggable-functions.php b/wp-includes/pluggable-functions.php
index 944ab5e8e4..6983ef7378 100644
--- a/wp-includes/pluggable-functions.php
+++ b/wp-includes/pluggable-functions.php
@@ -239,7 +239,7 @@ endif;
 
 if ( !function_exists('check_ajax_referer') ) :
 function check_ajax_referer() {
-	$cookie = explode(';', urldecode(empty($_POST['cookie']) ? $_GET['cookie'] : $_POST['cookie'])); // AJAX scripts must pass cookie=document.cookie
+	$cookie = explode('; ', urldecode(empty($_POST['cookie']) ? $_GET['cookie'] : $_POST['cookie'])); // AJAX scripts must pass cookie=document.cookie
 	foreach ( $cookie as $tasty ) {
 		if ( false !== strpos($tasty, USER_COOKIE) )
 			$user = substr(strstr($tasty, '='), 1);