diff --git a/Crypto/requirements.txt b/Crypto/requirements.txt
index bab5d42..1a6c0ea 100644
--- a/Crypto/requirements.txt
+++ b/Crypto/requirements.txt
@@ -5,7 +5,7 @@ chardet==3.0.4
 et-xmlfile==1.0.1
 idna==2.6
 jdcal==1.3
-lxml==4.1.1
+lxml==4.6.5
 numpy==1.14.0
 openpyxl==2.4.10
 pandas==0.22.0