diff --git a/core/modules/media_library/src/Plugin/Field/FieldWidget/MediaLibraryWidget.php b/core/modules/media_library/src/Plugin/Field/FieldWidget/MediaLibraryWidget.php
index 017c99e65be..3f341f54b06 100644
--- a/core/modules/media_library/src/Plugin/Field/FieldWidget/MediaLibraryWidget.php
+++ b/core/modules/media_library/src/Plugin/Field/FieldWidget/MediaLibraryWidget.php
@@ -305,7 +305,8 @@ class MediaLibraryWidget extends WidgetBase implements TrustedCallbackInterface
     $element += [
       '#type' => 'fieldset',
       '#cardinality' => $this->fieldDefinition->getFieldStorageDefinition()->getCardinality(),
-      '#target_bundles' => $settings['target_bundles'] ?? FALSE,
+      // If no target bundles are specified, all target bundles are allowed.
+      '#target_bundles' => $settings['target_bundles'] ?? [],
       '#attributes' => [
         'id' => $wrapper_id,
         'class' => ['js-media-library-widget'],
diff --git a/core/modules/media_library/tests/src/FunctionalJavascript/EntityReferenceWidgetTest.php b/core/modules/media_library/tests/src/FunctionalJavascript/EntityReferenceWidgetTest.php
index 53400620ec1..5ec06908ffe 100644
--- a/core/modules/media_library/tests/src/FunctionalJavascript/EntityReferenceWidgetTest.php
+++ b/core/modules/media_library/tests/src/FunctionalJavascript/EntityReferenceWidgetTest.php
@@ -140,7 +140,12 @@ class EntityReferenceWidgetTest extends MediaLibraryTestBase {
     $this->assertTrue($menu->hasLink('Type Three'));
     $this->assertTrue($menu->hasLink('Type Four'));
     $this->assertTrue($menu->hasLink('Type Five'));
-    $assert_session->elementExists('css', '.ui-dialog-titlebar-close')->click();
+
+    // Insert media to test validation with null target_bundles.
+    $this->switchToMediaType('One');
+    $this->assertNotEmpty($assert_session->waitForText('Showing Type One media.'));
+    $this->selectMediaItem(0);
+    $this->pressInsertSelected('Added one media item.');
 
     // Assert that the media type menu is not available when only 1 type is
     // configured for the field.