diff --git a/requirements.txt b/requirements.txt
index 4798f2e..c493a0a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -46,7 +46,7 @@ Jinja2==2.10.1
 JSON-minify==0.3.0
 jsonschema==3.0.1
 jupyter-core==4.5.0
-lxml==4.3.4
+lxml==4.9.1
 MarkupSafe==1.1.1
 more-itertools==7.0.0
 nbformat==4.4.0