diff --git a/requirements.txt b/requirements.txt
index eccdf12..2ecf5ef 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -34,7 +34,7 @@ numpy==1.18.1
 oauth2client==3.0.0
 pdfkit==0.6.1
 Pillow==7.0.0
-protobuf==3.11.2
+protobuf==3.18.3
 pyasn1==0.4.8
 pyasn1-modules==0.2.8
 pycryptodome==3.4.3