Ticket #28163: user.php.patch

src/wp-includes/user.php

@@ -1526 +1526 @@
  * @return bool|int The user's ID on success, and false on failure.
  */
 function email_exists( $email ) {
-        if ( $user = get_user_by('email', $email) )
+        $sanitize_email = sanitize_email( $email );
+        if ( $user = get_user_by('email', $sanitize_email) )
                 return $user->ID;
 
         return false;