diff --git a/Modules/cPickle.c b/Modules/cPickle.c
index 90e56109435..a73a7874f5e 100644
--- a/Modules/cPickle.c
+++ b/Modules/cPickle.c
@@ -3865,6 +3865,7 @@ newUnpicklerobject(PyObject *f) {
     self->buf_size = 0;
     self->read = NULL;
     self->readline = NULL;
+    self->safe_constructors = NULL;
 
     UNLESS (self->memo = PyDict_New()) {
        Py_XDECREF((PyObject *)self);