diff --git a/core/lib/Drupal/Core/Field/FieldConfigBase.php b/core/lib/Drupal/Core/Field/FieldConfigBase.php
index e25d94f..fa34ca3 100644
--- a/core/lib/Drupal/Core/Field/FieldConfigBase.php
+++ b/core/lib/Drupal/Core/Field/FieldConfigBase.php
@@ -146,7 +146,7 @@
    *
    * @var array
    */
-  protected $default_value = array();
+  public $default_value = array();
 
   /**
    * The name of a callback function that returns default values.