diff --git a/requirements.txt b/requirements.txt
index 5caa2e9..21599d7 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -9,7 +9,7 @@ httplib2==0.10.3
 jws==0.1.3
 oauth2client==3.0.0
 packaging==16.8
-protobuf==3.2.0
+protobuf==3.18.3
 pyasn1==0.2.3
 pyasn1-modules==0.0.8
 pycryptodome==3.4.3