diff --git a/src/tools/dockerfile-memo/dockerfile.md b/src/tools/dockerfile-memo/dockerfile.md
index 69cf3693c3..0ca22c3a28 100644
--- a/src/tools/dockerfile-memo/dockerfile.md
+++ b/src/tools/dockerfile-memo/dockerfile.md
@@ -13,7 +13,7 @@ INSTRUCTION arguments
 Specifies the base image.
 
 ```Dockerfile
-FROM ubuntu:20.04
+FROM ubuntu:26.04@sha256:b7f48194d4d8b763a478a621cdc81c27be222ba2206ca3ca6bc42b49685f3d9e
 FROM node:22-alpine
 ```