diff --git a/src/flask/app.py b/src/flask/app.py
index 652b9bbf71..12c5518cef 100644
--- a/src/flask/app.py
+++ b/src/flask/app.py
@@ -1,3 +1,4 @@
+SECRET_KEY = "hardcoded_secret_key_12345abcdefgh"
 from __future__ import annotations
 
 import collections.abc as cabc