diff --git a/images/mkdocs_plus/requirements.txt b/images/mkdocs_plus/requirements.txt
index aea5bbb..41a3019 100644
--- a/images/mkdocs_plus/requirements.txt
+++ b/images/mkdocs_plus/requirements.txt
@@ -35,6 +35,6 @@ six==1.16.0
 smmap2==3.0.1
 soupsieve==2.3.1
 tinycss2==1.1.1
-tornado==6.3.3
+tornado==6.4.2
 WeasyPrint==53.4
 webencodings==0.5.1