diff --git a/requirements.txt b/requirements.txt
index c9394be..fe2bdb3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -43,7 +43,7 @@ jupyterthemes==0.20.0
 kiwisolver==1.3.1
 lazy-object-proxy==1.4.3
 lesscpy==0.14.0
-lxml==4.5.2
+lxml==4.9.1
 MarkupSafe==1.1.1
 matplotlib==3.3.2
 mccabe==0.6.1