diff --git a/nginx-aspnet-mysql/backend/Dockerfile b/nginx-aspnet-mysql/backend/Dockerfile
index 6636f40..c565dda 100755
--- a/nginx-aspnet-mysql/backend/Dockerfile
+++ b/nginx-aspnet-mysql/backend/Dockerfile
@@ -1,6 +1,6 @@
 # syntax=docker/dockerfile:1.4
 
-FROM --platform=$BUILDPLATFORM mcr.microsoft.com/dotnet/sdk:6.0 AS base
+FROM --platform=$BUILDPLATFORM mcr.microsoft.com/dotnet/sdk:6.0@sha256:2fdad630a59fbdecbfcc6aaf3ccae96eea0e8d24cd4607669fde0de107a94c53 AS base
 
 WORKDIR /src