diff --git a/requirement.txt b/requirement.txt
index fa044a1..da2719e 100644
--- a/requirement.txt
+++ b/requirement.txt
@@ -20,7 +20,7 @@ jupyter-client==5.2.4
 jupyter-console==6.0.0
 jupyter-core==4.4.0
 kiwisolver==1.0.1
-lxml==4.3.0
+lxml==4.9.1
 MarkupSafe==1.1.0
 matplotlib==3.0.2
 mistune==0.8.4