diff --git a/requirements.txt b/requirements.txt
index 2d92c39..85dd5a3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -6,7 +6,7 @@ cssutils==1.0.2
 et-xmlfile==1.0.1
 idna==2.10
 jdcal==1.4.1
-lxml==4.6.5
+lxml==4.9.1
 numpy==1.19.4
 openpyxl==3.0.5
 pandas==1.2.0