diff --git a/core/modules/field/modules/text/lib/Drupal/text/Plugin/field/formatter/TextTrimmedFormatter.php b/core/modules/field/modules/text/lib/Drupal/text/Plugin/field/formatter/TextTrimmedFormatter.php
index 349cf63..8ad863b 100644
--- a/core/modules/field/modules/text/lib/Drupal/text/Plugin/field/formatter/TextTrimmedFormatter.php
+++ b/core/modules/field/modules/text/lib/Drupal/text/Plugin/field/formatter/TextTrimmedFormatter.php
@@ -44,6 +44,7 @@ public function settingsForm(array $form, array &$form_state) {
       '#title' => t('Trim length'),
       '#type' => 'number',
       '#default_value' => $this->getSetting('trim_length'),
+      '#element_validate' => array('element_validate_integer_positive'),
       '#min' => 1,
       '#required' => TRUE,
     );