diff --git a/requirements.txt b/requirements.txt
index 4eaa05d..7f18327 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -27,7 +27,7 @@ httplib2==0.18.1
 idna==2.10
 install==1.3.3
 jsonseq==1.0.0
-lxml==4.5.2
+lxml==4.9.1
 Markdown==3.2.2
 multidict==4.7.6
 numpy==1.19.0