diff --git a/Misc/NEWS b/Misc/NEWS
index 1dff486842a..2f387e7475a 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -166,6 +166,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #18559: Fix NULL pointer dereference error in _pickle module
+
 - Issue #18556: Check the return type of PyUnicode_AsWideChar() in ctype's
   U_set().
 
diff --git a/Modules/_pickle.c b/Modules/_pickle.c
index 4ba185d4b47..af73a847638 100644
--- a/Modules/_pickle.c
+++ b/Modules/_pickle.c
@@ -4836,9 +4836,10 @@ load_binget(UnpicklerObject *self)
     value = _Unpickler_MemoGet(self, idx);
     if (value == NULL) {
         PyObject *key = PyLong_FromSsize_t(idx);
-        if (!PyErr_Occurred())
+        if (key != NULL) {
             PyErr_SetObject(PyExc_KeyError, key);
-        Py_DECREF(key);
+            Py_DECREF(key);
+        }
         return -1;
     }
 
@@ -4861,9 +4862,10 @@ load_long_binget(UnpicklerObject *self)
     value = _Unpickler_MemoGet(self, idx);
     if (value == NULL) {
         PyObject *key = PyLong_FromSsize_t(idx);
-        if (!PyErr_Occurred())
+        if (key != NULL) {
             PyErr_SetObject(PyExc_KeyError, key);
-        Py_DECREF(key);
+            Py_DECREF(key);
+        }
         return -1;
     }