diff --git a/requirements.txt b/requirements.txt
index e9c24a4..331adef 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,7 +7,7 @@ html-text==0.5.2
 html5lib==1.1
 idna==2.10
 isodate==0.6.0
-lxml==4.5.2
+lxml==4.9.1
 mf2py==1.1.2
 more-itertools==8.5.0
 packaging==20.4