diff --git a/requirements.txt b/requirements.txt
index 5a0274d..c296dd7 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -50,7 +50,7 @@ kiwisolver==1.3.1
 lazy-object-proxy==1.6.0
 lockfile==0.12.2
 luigi==3.0.2
-lxml==4.7.1
+lxml==4.9.1
 MarkupSafe==1.1.1
 matplotlib==3.3.4
 matplotlib-inline==0.1.3