diff --git a/Misc/NEWS b/Misc/NEWS
index f0ba8c621345bf..8726996a4bc18c 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,9 @@ What's New in Python 2.7.14?
 Core and Builtins
 -----------------
 
+- bpo-29347: Fixed possibly dereferencing undefined pointers
+  when creating weakref objects.
+
 - Issue #14376: Allow sys.exit to accept longs as well as ints. Patch
   by Gareth Rees.
 
diff --git a/Objects/weakrefobject.c b/Objects/weakrefobject.c
index c8b982fcd59ce8..2eb4fe0b17fbf0 100644
--- a/Objects/weakrefobject.c
+++ b/Objects/weakrefobject.c
@@ -24,6 +24,8 @@ init_weakref(PyWeakReference *self, PyObject *ob, PyObject *callback)
 {
     self->hash = -1;
     self->wr_object = ob;
+    self->wr_prev = NULL;
+    self->wr_next = NULL;
     Py_XINCREF(callback);
     self->wr_callback = callback;
 }