diff --git a/Dockerfile b/Dockerfile
index fd2e796..4bc26ce 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ghcr.io/cybozu/ubuntu:22.04.20231204 as certs
+FROM ghcr.io/cybozu/ubuntu:22.04.20231207 as certs
 
 FROM scratch
 LABEL org.opencontainers.image.authors="Hsn723" \