diff --git a/core/privilege-helper.cpp b/core/privilege-helper.cpp
index ba3da78..b0ca116 100644
--- a/core/privilege-helper.cpp
+++ b/core/privilege-helper.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2014-2015,  Regents of the University of California,
+/*
+ * Copyright (c) 2014-2017,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -29,6 +29,8 @@
 #include <pwd.h>
 #include <grp.h>
 
+#include <sstream>
+
 namespace nfd {
 
 NFD_LOG_INIT("PrivilegeHelper");