Ticket #54748: wp-signup.php.patch

wp-signup.php

@@ -296 +296 @@
  *               See wpmu_validate_user_signup() for details.
  */
 function validate_user_form() {
-        return wpmu_validate_user_signup( $_POST['user_name'], $_POST['user_email'] );
+        return wpmu_validate_user_signup( sanitize_text_field($_POST['user_name']), sanitize_email($_POST['user_email']) );
 }
 
 /**