diff --git a/requirements.txt b/requirements.txt
index 7cc3b66..5410518 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -86,7 +86,7 @@ lazy-object-proxy==1.3.1
 livereload==2.6.0
 llvmlite
 locket==0.2.0
-lxml==4.2.1
+lxml==4.9.1
 Markdown==2.6.11
 MarkupSafe==1.0
 matplotlib==2.2.3