diff --git a/lower-constraints.txt b/lower-constraints.txt
index 34ae760e63..2471ddeb8a 100644
--- a/lower-constraints.txt
+++ b/lower-constraints.txt
@@ -48,7 +48,7 @@ keystoneauth1==3.15.0
 keystonemiddleware==4.20.0
 kombu==4.1.0
 linecache2==1.0.0
-lxml==3.4.1
+lxml==4.6.3
 Mako==1.0.7
 MarkupSafe==1.0
 mccabe==0.2.1