diff --git a/requirements.txt b/requirements.txt
index d29aa82..5d2c51f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -72,7 +72,7 @@ statsmodels==0.10.1
 terminado==0.8.2
 testpath==0.4.2
 toolz==0.10.0
-tornado==6.0.3
+tornado==6.4.2
 traitlets==4.3.2
 urllib3==1.26.5
 vega-datasets==0.7.0