diff --git a/lambdas/preview/requirements.txt b/lambdas/preview/requirements.txt
index d1450df5fcf..8a900f5ae2b 100644
--- a/lambdas/preview/requirements.txt
+++ b/lambdas/preview/requirements.txt
@@ -41,7 +41,7 @@ six==1.12.0
 soupsieve==2.4.1
 testpath==0.4.2
 tinycss2==1.2.1
-tornado==6.3.3
+tornado==6.4.1
 traitlets==5.3.0
 typing_extensions==4.5.0
 urllib3==1.26.18