diff --git a/mirror/1.21/Dockerfile b/mirror/1.21/Dockerfile
index 77385d2a..c5ca684f 100644
--- a/mirror/1.21/Dockerfile
+++ b/mirror/1.21/Dockerfile
@@ -7,7 +7,7 @@
 
 # https://hub.docker.com/_/golang
 
-FROM golang:1.21.2-bookworm
+FROM golang:1.21.3-bookworm
 
 # https://docs.github.com/en/packages/learn-github-packages/connecting-a-repository-to-a-package
 LABEL org.opencontainers.image.source="https://github.com/atc0005/go-ci"