diff --git a/lib/http-proxy/common.js b/lib/http-proxy/common.js
index 6513e81d80d5250ea249ea833f819ece67897c7e..0555e80e25b8c4f4f21281e38c4c04069009dc0c 100644
--- a/lib/http-proxy/common.js
+++ b/lib/http-proxy/common.js
@@ -1,6 +1,6 @@
 var common   = exports,
     url      = require('url'),
-    extend   = require('util')._extend,
+    extend   = Object.assign,
     required = require('requires-port');
 
 var upgradeHeader = /(^|,)\s*upgrade\s*($|,)/i,
diff --git a/lib/http-proxy/index.js b/lib/http-proxy/index.js
index 977a4b3622b9eaac27689f06347ea4c5173a96cd..739409c0dd0b93149fd174f4b085c3fbb522bf75 100644
--- a/lib/http-proxy/index.js
+++ b/lib/http-proxy/index.js
@@ -1,5 +1,5 @@
 var httpProxy = module.exports,
-    extend    = require('util')._extend,
+    extend    = Object.assign,
     parse_url = require('url').parse,
     EE3       = require('eventemitter3'),
     http      = require('http'),