Index: Modules/_multiprocessing/socket_connection.c
===================================================================
--- Modules/_multiprocessing/socket_connection.c	(revision 66438)
+++ Modules/_multiprocessing/socket_connection.c	(working copy)
@@ -158,6 +158,13 @@
 	int res;
 	fd_set rfds;
 
+	if (((int)conn->handle) < 0 || ((int)conn->handle) >= FD_SETSIZE) {
+		Py_BLOCK_THREADS
+		PyErr_SetString(PyExc_IOError, "handle out of range in select()");
+		Py_UNBLOCK_THREADS
+		return MP_EXCEPTION_HAS_BEEN_SET;
+	}
+
 	FD_ZERO(&rfds);
 	FD_SET((SOCKET)conn->handle, &rfds);