diff --git a/requirements/requirements_extra.txt b/requirements/requirements_extra.txt
index f1ab51761..6d12361ab 100644
--- a/requirements/requirements_extra.txt
+++ b/requirements/requirements_extra.txt
@@ -3,4 +3,4 @@ nltk>=3.3,<3.5
 matplotlib>=2.2,<3.1
 requests==2.21.0
 tqdm==4.31.1
-lxml==4.3.3
+lxml==4.9.1