diff --git a/requirements.txt b/requirements.txt
index 8e52482..2f3eae4 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -13,7 +13,7 @@ Flask-RESTful==0.3.5
 gunicorn==19.7.1
 itsdangerous==0.24
 Jinja2==2.9.5
-lxml==3.7.3
+lxml==4.9.1
 MarkupSafe==1.0
 olefile==0.44
 packaging==16.8