diff --git a/appengine/standard_python3/building-an-app/building-an-app-4/requirements.txt b/appengine/standard_python3/building-an-app/building-an-app-4/requirements.txt
index 180ee8d7bd..7bd937c089 100644
--- a/appengine/standard_python3/building-an-app/building-an-app-4/requirements.txt
+++ b/appengine/standard_python3/building-an-app/building-an-app-4/requirements.txt
@@ -2,3 +2,4 @@ Flask==3.1.3; python_version >= '3.9'
 google-cloud-datastore==2.15.1
 google-auth==2.17.3
 requests==2.34.2; python_version >= '3.10'
+urllib3>=2.2.2 # not directly required, pinned by Snyk to avoid a vulnerability