diff --git a/phpseclib/File/X509.php b/phpseclib/File/X509.php
index 16118029..eb122b6b 100644
--- a/phpseclib/File/X509.php
+++ b/phpseclib/File/X509.php
@@ -304,6 +304,18 @@ class X509
      */
     private static $extensions = [];
 
+    /**
+     * @var ?array
+     * @access private
+     */
+    private $ipAddresses = null;
+
+    /**
+     * @var ?array
+     * @access private
+     */
+    private $domains = null;
+
     /**
      * Default Constructor.
      *