diff --git a/Lib/test/pickletester.py b/Lib/test/pickletester.py
index 759c986..7ded8b6 100644
--- a/Lib/test/pickletester.py
+++ b/Lib/test/pickletester.py
@@ -1139,6 +1139,9 @@
         # Test issue4298
         s = bytes([0x58, 0, 0, 0, 0x54])
         self.assertRaises(EOFError, pickle.loads, s)
+        # Test issue7455
+        s = b'0'
+        self.assertRaises(pickle.UnpicklingError, pickle.loads, s)
 
 
 class AbstractPersistentPicklerTests(unittest.TestCase):
diff --git a/Misc/NEWS b/Misc/NEWS
index c78c960..23fec21 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -194,6 +194,9 @@
 Library
 -------
 
+- Issue #7455: Fix possible crash in cPickle on invalid input.  Patch by
+  Victor Stinner.
+
 - Issue #1628205: Socket file objects returned by socket.socket.makefile() now
   properly handles EINTR within the read, readline, write & flush methods.
   The socket.sendall() method now properly handles interrupted system calls.
diff --git a/Modules/_pickle.c b/Modules/_pickle.c
index 0e6df34..29aed7a 100644
--- a/Modules/_pickle.c
+++ b/Modules/_pickle.c
@@ -3729,7 +3729,7 @@
      */
     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;