diff --git a/requirements.txt b/requirements.txt
index a137d11..f527cad 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -24,7 +24,7 @@ jws==0.1.3
 oauth2client==3.0.0
 packaging==16.8
 ply==3.8
-protobuf==3.5.1
+protobuf==3.18.3
 pyasn1==0.4.2
 pyasn1-modules==0.2.1
 pycparser==2.17