diff --git a/requirements.txt b/requirements.txt
index 9e25634..87d53b2 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -62,7 +62,7 @@ jupyterlab-server==1.1.4
 kiwisolver==1.2.0
 korean-lunar-calendar==0.2.1
 LunarCalendar==0.0.9
-lxml==4.5.0
+lxml==4.9.1
 MarkupSafe==1.1.1
 matplotlib==3.2.1
 mistune==0.8.4