diff --git a/Dockerfile b/Dockerfile
index 5952d00..adb368f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,6 @@
 # bump: golang /FROM golang:([\d.]+)/ docker:golang|^1
 # bump: golang link "Release notes" https://golang.org/doc/devel/release.html
-FROM golang:1.21.0-bookworm AS builder
+FROM golang:1.21.1-bookworm AS builder
 
 # patch is used by cmd/bump/main_test.sh to test diff
 RUN apt update && apt install -y patch