diff -u b/core/modules/system/lib/Drupal/system/Tests/Session/SessionHttpsTest.php b/core/modules/system/lib/Drupal/system/Tests/Session/SessionHttpsTest.php
--- b/core/modules/system/lib/Drupal/system/Tests/Session/SessionHttpsTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Session/SessionHttpsTest.php
@@ -231,7 +231,7 @@
   protected function assertSessionIds($sid, $ssid, $assertion_text) {
     $args = array(
       ':sid' => Crypt::hashBase64($sid),
-      ':ssid' => Crypt::hashBase64($ssid),
+      ':ssid' => !empty($ssid) ? Crypt::hashBase64($ssid) : '',
     );
     return $this->assertTrue(db_query('SELECT timestamp FROM {sessions} WHERE sid = :sid AND ssid = :ssid', $args)->fetchField(), $assertion_text);
   }