diff --git a/requirements.txt b/requirements.txt
index 3acd0c8..4faa658 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -36,7 +36,7 @@ jupyter-client==5.2.4
 jupyter-console==6.0.0
 jupyter-core==4.5.0
 kiwisolver==1.1.0
-lxml==4.3.4
+lxml==4.9.1
 Markdown==3.1.1
 MarkupSafe==1.1.1
 matplotlib==3.1.1