diff --git a/requirements.txt b/requirements.txt
index 70e297d..8cb96f7 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -26,7 +26,7 @@ idna==2.2
 incremental==16.10.1
 itsdangerous==0.24
 Jinja2==2.9.5
-lxml==3.7.3
+lxml==4.9.1
 Mako==1.0.6
 Markdown==2.6.8
 MarkupSafe==0.23