fixed issue #192
diff --git a/system/core/Security.php b/system/core/Security.php
index e99418b..6c4c590 100755
--- a/system/core/Security.php
+++ b/system/core/Security.php
@@ -169,6 +169,7 @@
 
 		// Nothing should last forever
 		unset($_COOKIE[$this->_csrf_cookie_name]);
+                $this->_csrf_hash = '';
 		$this->_csrf_set_hash();
 		$this->csrf_set_cookie();