diff --git a/lib/util.js b/lib/util.js
index cfbfbaf5..24e2641a 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -188,7 +188,7 @@ exports.selectiveExtend = function (props, a, b) {
 
     for (var p = 0; p < props.length; p++) {
       var prop = props[p];
-      if (other.hasOwnProperty(prop)) {
+      if (other && other.hasOwnProperty(prop)) {
         a[prop] = other[prop];
       }
     }