diff --git a/Dockerfile b/Dockerfile
index 1031779..6efa965 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM python:3.9-alpine
+FROM python:3.9-alpine@sha256:0267b3631f06804da6b1a66c3b399e6335ed394d04d8c714b7a4dfa866c35337
 
 LABEL maintainer="Robert Kaussow <mail@thegeeklab.de>"
 LABEL org.opencontainers.image.authors="Robert Kaussow <mail@thegeeklab.de>"