diff --git a/mail/requirements.txt b/mail/requirements.txt
index 2d682e4..607f8c0 100644
--- a/mail/requirements.txt
+++ b/mail/requirements.txt
@@ -20,7 +20,7 @@ mccabe==0.6.1
 oauthlib==3.1.0
 packaging==20.9
 pip==21.1
-protobuf==3.15.8
+protobuf==3.18.3
 pyasn1==0.4.8
 pyasn1-modules==0.2.8
 pyparsing==2.4.7