diff --git a/requirements.txt b/requirements.txt
index 592a6f0..8c5b10a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,7 +5,7 @@ fastapi==0.65.2
 fpdf==1.7.2
 h11==0.9.0
 httptools==0.1.1
-lxml==4.6.5
+lxml==4.9.1
 pdf-diff==0.9.1
 Pillow==8.3.2
 pydantic==1.6.2