diff --git a/requirements.txt b/requirements.txt
index 5fb2bba..10baf8e 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -11,7 +11,7 @@ requests==2.26.0
 tqdm==4.46.1
 joblib==0.16.0
 sklearn_crfsuite==0.3.6
-lxml==4.6.5
+lxml==4.9.1
 pytest==6.0.2
 pytest-cov==2.10.1
 pytest-mock==3.3.1