diff --git a/requirements.txt b/requirements.txt
index 9d7fc4a..8eb5558 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -76,7 +76,7 @@ lazy-object-proxy==1.3.1
 llvmlite==0.20.0
 locket==0.2.0
 lockfile==0.12.2
-lxml==4.1.0
+lxml==4.9.1
 MarkupSafe==1.0
 matplotlib==2.1.0
 mccabe==0.6.1