diff --git a/requirements.txt b/requirements.txt
index 395b6a8..38c5271 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -19,7 +19,7 @@ jupyter-client==5.3.4
 jupyter-core==4.6.1
 kiwisolver==1.1.0
 livereload==2.6.1
-lxml==4.5.0
+lxml==4.9.1
 Markdown==3.2
 MarkupSafe==1.1.1
 matplotlib==3.1.3