diff --git a/cmd/python/functions_framework_compat/converter/requirements.txt b/cmd/python/functions_framework_compat/converter/requirements.txt
index ad97f7b..144b214 100644
--- a/cmd/python/functions_framework_compat/converter/requirements.txt
+++ b/cmd/python/functions_framework_compat/converter/requirements.txt
@@ -22,7 +22,7 @@ MarkupSafe==1.1.1
 multidict==4.7.6
 opencensus==0.7.9
 opencensus-context==0.1.1
-protobuf==3.15.0
+protobuf==3.18.3
 pyasn1==0.4.8
 pyasn1-modules==0.2.8
 pytz==2020.1