diff --git a/requirements.txt b/requirements.txt
index 4360121..43516fd 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -72,7 +72,7 @@ jupyterlab-launcher==0.4.0
 lazy-object-proxy==1.3.1
 llvmlite==0.20.0
 locket==0.2.0
-lxml==4.1.1
+lxml==4.9.1
 MarkupSafe==1.0
 matplotlib==2.1.0
 mccabe==0.6.1