diff --git a/requirements.txt b/requirements.txt
index 72f9bd2..181cd86 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -14,7 +14,7 @@ html5lib==0.999
 idna==2.1
 inflection==0.3.1
 ipaddress==1.0.16
-lxml==3.6.0
+lxml==4.9.1
 Mako==1.0.4
 MarkupSafe==0.23
 ndg-httpsclient==0.4.0