Update to Drupal 8.2.6. For more information, see https://www.drupal.org/project/drupal/releases/8.2.6

update.php

@@ -13,6 +13,15 @@ use Symfony\Component\HttpFoundation\Request;
 
 $autoloader = require_once 'autoload.php';
 
+// Disable garbage collection during test runs. Under certain circumstances the
+// update path will create so many objects that garbage collection causes
+// segmentation faults.
+require_once 'core/includes/bootstrap.inc';
+if (drupal_valid_test_ua()) {
+  gc_collect_cycles();
+  gc_disable();
+}
+
 $kernel = new UpdateKernel('prod', $autoloader, FALSE);
 $request = Request::createFromGlobals();