diff --git a/requirements.txt b/requirements.txt
index 9352990..c213bdc 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -168,7 +168,7 @@ linecache2==1.0.0
 llvmlite==0.20.0
 llvmpy==0.12.7
 locket==0.2.0
-lxml==3.3.5
+lxml==4.6.3
 Markdown==2.6.11
 MarkupSafe==0.23
 marshmallow==2.15.0