diff --git a/requirements.txt b/requirements.txt
index d39dca2..f7c6152 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -105,7 +105,7 @@ traitlets==4.3.2
 typed-ast==1.4.0
 urllib3==1.25.3
 virtualenv==16.7.2
-waitress==1.4.2
+waitress==1.4.3
 wcwidth==0.1.7
 webencodings==0.5.1
 WebOb==1.8.5