diff --git a/UNITTESTS/features/netsocket/InternetSocket/test_InternetSocket.cpp b/UNITTESTS/features/netsocket/InternetSocket/test_InternetSocket.cpp
index 859f1eb964..bf3424869f 100644
--- a/UNITTESTS/features/netsocket/InternetSocket/test_InternetSocket.cpp
+++ b/UNITTESTS/features/netsocket/InternetSocket/test_InternetSocket.cpp
@@ -222,6 +222,7 @@ TEST_F(TestInternetSocket, getsockopt)
 TEST_F(TestInternetSocket, sigio)
 {
     callback_is_called = false;
+    socket->open((NetworkStack *)&stack);
     socket->sigio(mbed::callback(my_callback));
     socket->close(); // Trigger event;
     EXPECT_EQ(callback_is_called, true);
diff --git a/features/netsocket/InternetSocket.cpp b/features/netsocket/InternetSocket.cpp
index 948e25374a..cc793450a2 100644
--- a/features/netsocket/InternetSocket.cpp
+++ b/features/netsocket/InternetSocket.cpp
@@ -56,6 +56,10 @@ nsapi_error_t InternetSocket::close()
     _lock.lock();
 
     nsapi_error_t ret = NSAPI_ERROR_OK;
+    if (!_stack)  {
+        return ret;
+    }
+
     if (_socket) {
         _stack->socket_attach(_socket, 0, 0);
         nsapi_socket_t socket = _socket;