diff --git a/requirements.txt b/requirements.txt
index a1d0112..b02337e 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -27,7 +27,7 @@ jsonpatch==1.25
 jsonpickle==1.4.1
 jsonpointer==2.0
 jsonschema==3.2.0
-lxml==4.4.1
+lxml==4.9.1
 MarkupSafe==1.1.1
 mock==4.0.2
 more-itertools==8.2.0