diff --git a/requirements.txt b/requirements.txt
index 38e7db1..36354ba 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -82,7 +82,7 @@ kiwisolver==1.0.1
 lazy-object-proxy==1.3.1
 llvmlite==0.23.1
 locket==0.2.0
-lxml==4.2.1
+lxml==4.9.1
 Markdown==3.2.2
 MarkupSafe==1.0
 matplotlib==2.2.2