diff --git a/requirements.txt b/requirements.txt
index bc50b3e..bb761f0 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -35,7 +35,7 @@ jupyter-highlight-selected-word==0.2.0
 jupyter-latex-envs==1.4.4
 jupyter-nbextensions-configurator==0.4.1
 kiwisolver==1.2.0
-lxml==4.5.0
+lxml==4.9.1
 MarkupSafe==1.1.1
 matplotlib==3.2.1
 mistune==0.8.4