Index: Modules/cPickle.c
===================================================================
--- Modules/cPickle.c	(révision 76754)
+++ Modules/cPickle.c	(copie de travail)
@@ -4117,7 +4117,7 @@
 	*/
 	if (self->num_marks > 0 && self->marks[self->num_marks - 1] == len) {
 		self->num_marks--;
-	} else if (len >= 0) {
+	} else if (len > 0) {
 		len--;
 		Py_DECREF(self->stack->data[len]);
 		self->stack->length = len;
Index: Lib/test/test_pickle.py
===================================================================
--- Lib/test/test_pickle.py	(révision 76754)
+++ Lib/test/test_pickle.py	(copie de travail)
@@ -21,6 +21,10 @@
     module = pickle
     error = KeyError
 
+    def test_invalid_pop(self):
+        self.assertRaises(IndexError, self.loads, "0")
+
+
 class PicklerTests(AbstractPickleTests):
 
     error = KeyError
Index: Lib/test/test_cpickle.py
===================================================================
--- Lib/test/test_cpickle.py	(révision 76754)
+++ Lib/test/test_cpickle.py	(copie de travail)
@@ -13,6 +13,10 @@
     error = cPickle.BadPickleGet
     module = cPickle
 
+    def test_invalid_pop(self):
+        self.assertRaises(cPickle.UnpicklingError, self.loads, "0")
+
+
 class cPicklePicklerTests(AbstractPickleTests):
 
     def dumps(self, arg, proto=0):