diff --git a/pip-sample/requirements.txt b/pip-sample/requirements.txt
index 1d7c58ab9..035b30471 100644
--- a/pip-sample/requirements.txt
+++ b/pip-sample/requirements.txt
@@ -59,3 +59,4 @@ webencodings==0.5.1
 Werkzeug==0.14.1
 widgetsnbextension==3.4.2
 xlrd==1.1.0
+tornado>=6.5.5 # not directly required, pinned by Snyk to avoid a vulnerability