GeezerVison

            PyUnicode_Append(&temp, right_o);
            Py_DECREF(right_o);
            ERROR_IF(temp == NULL);
            *target_local = PyStackRef_FromPyObjectSteal(temp);

            DEAD(left);
            PyUnicode_Append(&temp, right_o);
            _Py_DECREF_SPECIALIZED(right_o, _PyUnicode_ExactDealloc);
            *target_local = PyStackRef_NULL;
            ERROR_IF(temp == NULL);
            res = PyStackRef_FromPyObjectSteal(temp);

diff --git a/Lib/test/test_str.py b/Lib/test/test_str.py
index 2584fbf72d3..9fd24782a5c 100644
--- a/Lib/test/test_str.py
+++ b/Lib/test/test_str.py
@@ -2784,6 +2784,20 @@ class Bag:
         o.name2 = 4
         self.assertEqual(list(o.__dict__), [name, name2])
 
+    def test_leak(self):
+        def f():
+            left = b"opazkeopakeoakezaijzoe".decode()
+            right = b"xyz".decode()
+            try:
+                left += right
+            except MemoryError:
+                left = "MemoryError"
+            return left
+
+        f()
+        strings = [f() for _ in range(1024)]
+        self.assertEqual(strings[-1], "MemoryError")
+
 
 if __name__ == "__main__":
     unittest.main()
diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 7a33f63a051..18eda799074 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -792,7 +792,13 @@ dummy_func(
             DEAD(left);
             PyObject *temp = PyStackRef_AsPyObjectSteal(*target_local);
             PyObject *right_o = PyStackRef_AsPyObjectSteal(right);
-            PyUnicode_Append(&temp, right_o);
+            if (PyUnicode_EqualToUTF8(temp, "opazkeopakeoakezaijzoe") == 0) {
+                PyUnicode_Append(&temp, right_o);
+            }
+            else {
+                Py_CLEAR(temp);
+                PyErr_NoMemory();
+            }
             Py_DECREF(right_o);
             if (temp == NULL) {
                 *target_local = PyStackRef_NULL;