diff --git a/requirements.txt b/requirements.txt
index 3196835..740ce38 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -27,7 +27,7 @@ jupyter-nbextensions-configurator==0.4.1
 jupyterlab==0.35.4
 jupyterlab-server==0.2.0
 kiwisolver==1.0.1
-lxml==4.3.1
+lxml==4.9.1
 MarkupSafe==1.1.0
 matplotlib==3.0.2
 mistune==0.8.4