diff --git a/src/cartservice/cartservice.csproj b/src/cartservice/cartservice.csproj
index 91a1c61..81d70ca 100644
--- a/src/cartservice/cartservice.csproj
+++ b/src/cartservice/cartservice.csproj
@@ -7,7 +7,7 @@
 
   <ItemGroup>
     <PackageReference Include="CommandLineParser" Version="2.2.1" />
-    <PackageReference Include="Google.Protobuf" Version="3.6.1" />
+    <PackageReference Include="Google.Protobuf" Version="3.15.0" />
     <PackageReference Include="Google.Protobuf.Tools" Version="3.5.1" />
     <PackageReference Include="grpc" Version="1.12.0" />
     <PackageReference Include="Grpc.HealthCheck" Version="1.15.0" />
diff --git a/tests/cartservice/cartservice.tests.csproj b/tests/cartservice/cartservice.tests.csproj
index 4ada297..9479ad8 100644
--- a/tests/cartservice/cartservice.tests.csproj
+++ b/tests/cartservice/cartservice.tests.csproj
@@ -7,7 +7,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Google.Protobuf" Version="3.6.0" />
+    <PackageReference Include="Google.Protobuf" Version="3.15.0" />
     <PackageReference Include="Google.Protobuf.Tools" Version="3.6.0" />
     <PackageReference Include="Grpc" Version="1.12.0" />
     <PackageReference Include="Grpc.Tools" Version="1.12.0" />