diff --git a/appengine/flexible/websockets/requirements.txt b/appengine/flexible/websockets/requirements.txt
index 43af37c2ae8..7f4298a2fab 100644
--- a/appengine/flexible/websockets/requirements.txt
+++ b/appengine/flexible/websockets/requirements.txt
@@ -2,3 +2,4 @@ Flask==1.0.2
 Flask-Sockets==0.2.1
 gunicorn==19.9.0
 requests==2.21.0
+urllib3>=2.6.0 # not directly required, pinned by Snyk to avoid a vulnerability