diff --git a/requirements.txt b/requirements.txt
index db4bf69e..402e3dff 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -19,7 +19,7 @@ Jinja2==2.11.2
 joblib==0.17.0
 kiwisolver==1.3.1
 latexcodec==2.0.1
-lxml==4.6.2
+lxml==4.9.1
 MarkupSafe==1.1.1
 matplotlib==3.3.3
 numpy==1.19.4