diff --git a/lib/node-http-proxy/http-proxy.js b/lib/node-http-proxy/http-proxy.js
index 1a893f8..ffd5c95 100644
--- a/lib/node-http-proxy/http-proxy.js
+++ b/lib/node-http-proxy/http-proxy.js
@@ -439,12 +439,15 @@ HttpProxy.prototype.proxyRequest = function (req, res, buffer) {
 // Performs a WebSocket proxy operation to the location specified by
 // `this.target`.
 //
-HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, buffer) {
+HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, upgradeHead, buffer) {
   var self      = this,
       outgoing  = new(this.target.base),
       listeners = {},
       errState  = false,
-      CRLF      = '\r\n';
+      CRLF      = '\r\n',
+      //copy upgradeHead to avoid retention of large slab buffers used in node core
+      head = new Buffer(upgradeHead.length);
+      upgradeHead.copy(head); 
 
   //
   // WebSocket requests must have the `GET` method and