diff --git a/requirements.txt b/requirements.txt
index e479cb6f..7f0b7194 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -35,7 +35,7 @@ dash_cytoscape>=0.1.1
 networkx==2.5
 chart-studio==1.0.0
 xhtml2pdf==0.2.4
-lxml==4.3.4
+lxml==4.9.1
 celery==5.0.5
 cffi>=1.14.0
 rpy2==3.0.5; platform_system!="Windows"