diff --git a/includes/form.inc b/includes/form.inc
index 13dd72a79..1db018421 100644
--- a/includes/form.inc
+++ b/includes/form.inc
@@ -1360,7 +1360,7 @@ function _form_validate(&$elements, &$form_state, $form_id = NULL) {
     // The following errors are always shown.
     if (isset($elements['#needs_validation'])) {
       // Verify that the value is not longer than #maxlength.
-      if (isset($elements['#maxlength']) && !is_scalar($elements['#value'])) {
+      if (isset($elements['#maxlength']) && (isset($elements['#value']) && !is_scalar($elements['#value']))) {
         form_error($elements, $t('An illegal value has been detected. Please contact the site administrator.'));
       }
       elseif (isset($elements['#maxlength']) && drupal_strlen($elements['#value']) > $elements['#maxlength']) {
diff --git a/modules/user/user.pages.inc b/modules/user/user.pages.inc
index 5f5c2192e..fe239fe5f 100644
--- a/modules/user/user.pages.inc
+++ b/modules/user/user.pages.inc
@@ -66,7 +66,7 @@ function user_pass() {
  * @see user_pass_submit()
  */
 function user_pass_validate($form, &$form_state) {
-  if (!is_scalar($form_state['values']['name'])) {
+  if (isset($form_state['values']['name']) && !is_scalar($form_state['values']['name'])) {
     form_set_error('name', t('An illegal value has been detected. Please contact the site administrator.'));
     return;
   }