diff --git a/lower-constraints.txt b/lower-constraints.txt
index 806426950..ab519b228 100644
--- a/lower-constraints.txt
+++ b/lower-constraints.txt
@@ -44,7 +44,7 @@ keystoneauth1==3.4.0
 keystonemiddleware==4.17.0
 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