diff --git a/requirements.txt b/requirements.txt
index 8ca0b63..614b303 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -33,7 +33,7 @@ intervaltree==2.1.0
 itsdangerous==1.1.0
 Jinja2==2.10
 jsonschema==3.0.1
-lxml==4.3.4
+lxml==4.9.1
 Mako==1.0.11
 MarkupSafe==1.1.1
 mistune==0.8.4