diff --git a/appengine/standard_python37/building-an-app/building-an-app-3/requirements.txt b/appengine/standard_python37/building-an-app/building-an-app-3/requirements.txt
index 029eca50f33..2d5b9030ece 100644
--- a/appengine/standard_python37/building-an-app/building-an-app-3/requirements.txt
+++ b/appengine/standard_python37/building-an-app/building-an-app-3/requirements.txt
@@ -2,3 +2,4 @@ Flask==1.0.2
 google-cloud-datastore==1.7.3
 google-auth==1.6.2
 requests==2.21.0
+urllib3>=2.6.0 # not directly required, pinned by Snyk to avoid a vulnerability