diff -r 6c2e2de5ab8e Objects/listobject.c
--- a/Objects/listobject.c	Sat Jul 30 23:51:13 2016 -0700
+++ b/Objects/listobject.c	Sun Jul 31 20:04:50 2016 +0800
@@ -808,6 +808,10 @@
             Py_RETURN_NONE;
         }
         m = Py_SIZE(self);
+        if (m > PY_SSIZE_T_MAX - n) {
+            Py_DECREF(b);
+            return PyErr_NoMemory();
+        }
         if (list_resize(self, m + n) < 0) {
             Py_DECREF(b);
             return NULL;