diff --git a/requirements.txt b/requirements.txt
index 655b9ec..1048f27 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -26,7 +26,7 @@ jupyter==1.0.0
 jupyter-client==5.3.1
 jupyter-console==6.0.0
 jupyter-core==4.5.0
-lxml==4.3.4
+lxml==4.9.1
 MarkupSafe==1.1.1
 mistune==0.8.4
 nbconvert==5.5.0