diff --git a/CHANGELOG.md b/CHANGELOG.md
index 75a605225..d473b567f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -386,3 +386,7 @@ Magento CE 1.8+ or EE 1.13+, see [these instructions](https://github.com/nexcess
   * [#796] Ignore additional GET Parameters in Varnish Cache via Configuration (@thampe)
   * [#626] Fix for dummy blocks not working (@jeroenvermeulen)
   * [#719) Replace connect20/nexcessnet_turpentine package in composer.json (@ihor-sviziev)
+
+### RELEASE-0.6.3
+  * [#499] Use rewrite instead of local Session model for form key handling (@eth8505)  
+
diff --git a/app/code/community/Nexcessnet/Turpentine/Model/Core/Session.php b/app/code/community/Nexcessnet/Turpentine/Model/Core/Session.php
new file mode 100644
index 000000000..7b2afa444
--- /dev/null
+++ b/app/code/community/Nexcessnet/Turpentine/Model/Core/Session.php
@@ -0,0 +1,53 @@
+<?php
+
+/**
+ * Nexcess.net Turpentine Extension for Magento
+ * Copyright (C) 2012  Nexcess.net L.L.C.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+class Nexcessnet_Turpentine_Model_Core_Session extends Mage_Core_Model_Session
+{
+    public function __construct($data=array())
+    {
+        $name = isset($data['name']) ? $data['name'] : null;
+        $this->init('core', $name);
+    }
+
+    /**
+     * Retrieve Session Form Key
+     *
+     * @return string A 16 bit unique key for forms
+     */
+    public function getFormKey()
+    {
+        if (Mage::registry('replace_form_key') &&
+                !Mage::app()->getRequest()->getParam('form_key', false)) {
+            // flag request for ESI processing
+            Mage::register('turpentine_esi_flag', true, true);
+            return '{{form_key_esi_placeholder}}';
+        } else {
+            return parent::getFormKey();
+        }
+    }
+
+    public function real_getFormKey()
+    {
+        if (!$this->getData('_form_key')) {
+            $this->setData('_form_key', Mage::helper('core')->getRandomString(16));
+        }
+        return $this->getData('_form_key');
+    }
+}
diff --git a/app/code/community/Nexcessnet/Turpentine/etc/config.xml b/app/code/community/Nexcessnet/Turpentine/etc/config.xml
index d50d43b0c..f67896000 100644
--- a/app/code/community/Nexcessnet/Turpentine/etc/config.xml
+++ b/app/code/community/Nexcessnet/Turpentine/etc/config.xml
@@ -20,7 +20,7 @@
 <config>
     <modules>
         <Nexcessnet_Turpentine>
-            <version>0.6.2</version>
+            <version>0.6.3</version>
         </Nexcessnet_Turpentine>
     </modules>
     <default>
@@ -136,6 +136,11 @@
             <turpentine>
                 <class>Nexcessnet_Turpentine_Model</class>
             </turpentine>
+            <core>
+                <rewrite>
+                    <session>Nexcessnet_Turpentine_Model_Core_Session</session>
+                </rewrite>
+            </core>
         </models>
         <cache>
             <types>
diff --git a/app/code/local/Mage/Core/Model/Session.php b/app/code/local/Mage/Core/Model/Session.php
deleted file mode 100644
index 4c701738f..000000000
--- a/app/code/local/Mage/Core/Model/Session.php
+++ /dev/null
@@ -1,69 +0,0 @@
-<?php
-/**
- * Magento
- *
- * NOTICE OF LICENSE
- *
- * This source file is subject to the Open Software License (OSL 3.0)
- * that is bundled with this package in the file LICENSE.txt.
- * It is also available through the world-wide-web at this URL:
- * http://opensource.org/licenses/osl-3.0.php
- * If you did not receive a copy of the license and are unable to
- * obtain it through the world-wide-web, please send an email
- * to license@magentocommerce.com so we can send you a copy immediately.
- *
- * DISCLAIMER
- *
- * Do not edit or add to this file if you wish to upgrade Magento to newer
- * versions in the future. If you wish to customize Magento for your
- * needs please refer to http://www.magentocommerce.com for more information.
- *
- * @category    Mage
- * @package     Mage_Core
- * @copyright   Copyright (c) 2013 Magento Inc. (http://www.magentocommerce.com)
- * @license     http://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
- */
-
-
-/**
- * Core session model
- *
- * @todo extend from Mage_Core_Model_Session_Abstract
- *
- * @method null|bool getCookieShouldBeReceived()
- * @method Mage_Core_Model_Session setCookieShouldBeReceived(bool $flag)
- * @method Mage_Core_Model_Session unsCookieShouldBeReceived()
- */
-class Mage_Core_Model_Session extends Mage_Core_Model_Session_Abstract
-{
-    public function __construct($data=array())
-    {
-        $name = isset($data['name']) ? $data['name'] : null;
-        $this->init('core', $name);
-    }
-
-    /**
-     * Retrieve Session Form Key
-     *
-     * @return string A 16 bit unique key for forms
-     */
-    public function getFormKey()
-    {
-        if (Mage::registry('replace_form_key') &&
-                !Mage::app()->getRequest()->getParam('form_key', false)) {
-            // flag request for ESI processing
-            Mage::register('turpentine_esi_flag', true, true);
-            return '{{form_key_esi_placeholder}}';
-        } else {
-            return $this->real_getFormKey();
-        }
-    }
-
-    public function real_getFormKey()
-    {
-        if (!$this->getData('_form_key')) {
-            $this->setData('_form_key', Mage::helper('core')->getRandomString(16));
-        }
-        return $this->getData('_form_key');
-    }
-}