diff --git a/requirements.txt b/requirements.txt
index e1af437..7ba316c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,7 +7,7 @@ pandas>=1.1.5
 networkx<2
 bidict==0.21.2
 matplotlib>=3.3.4
-lxml==4.6.5
+lxml==4.9.1
 pydot==1.4.2
 spacy[lookups]==3.0.6
 joblib==1.0.1