diff --git a/requirements.txt b/requirements.txt
index 35f27d4..27c5b69 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -29,7 +29,7 @@ jupyter-nbextensions-configurator==0.4.1
 jupyterlab==1.2.3
 jupyterlab-server==1.0.6
 kiwisolver==1.1.0
-lxml==4.4.1
+lxml==4.9.1
 MarkupSafe==1.1.1
 matplotlib==3.1.1
 mistune==0.8.4