diff --git a/app/Dockerfile b/app/Dockerfile
index dc3de69..3abb8fc 100644
--- a/app/Dockerfile
+++ b/app/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine:3.9
+FROM alpine:3.24@sha256:294b683cb724975bec92580e1e685676bd4b50bda910ddb8c51d4cabeaec77e6
 ADD app /
 ADD index.html.tmpl /
 EXPOSE 80