diff --git a/docker/Dockerfile.amd64 b/docker/Dockerfile.amd64
index 2b19909..42221c0 100644
--- a/docker/Dockerfile.amd64
+++ b/docker/Dockerfile.amd64
@@ -1,4 +1,4 @@
-FROM amd64/python:3.9-alpine
+FROM amd64/python:3.9-alpine@sha256:0267b3631f06804da6b1a66c3b399e6335ed394d04d8c714b7a4dfa866c35337
 
 LABEL maintainer="Robert Kaussow <mail@thegeeklab.de>"
 LABEL org.opencontainers.image.authors="Robert Kaussow <mail@thegeeklab.de>"
diff --git a/docker/Dockerfile.arm b/docker/Dockerfile.arm
index 2baae0e..6a6a01b 100644
--- a/docker/Dockerfile.arm
+++ b/docker/Dockerfile.arm
@@ -1,4 +1,4 @@
-FROM arm32v7/python:3.9-alpine
+FROM arm32v7/python:3.9-alpine@sha256:6286e21b9e3472294444c4d7ae04b571ef342f26dfa828643bb3fea4ea2df708
 
 LABEL maintainer="Robert Kaussow <mail@thegeeklab.de>"
 LABEL org.opencontainers.image.authors="Robert Kaussow <mail@thegeeklab.de>"
diff --git a/docker/Dockerfile.arm64 b/docker/Dockerfile.arm64
index 30a0758..b3577ff 100644
--- a/docker/Dockerfile.arm64
+++ b/docker/Dockerfile.arm64
@@ -1,4 +1,4 @@
-FROM arm64v8/python:3.9-alpine
+FROM arm64v8/python:3.9-alpine@sha256:967915ae7fd5154ec94d32f884e59dc7e5a46a7f71f0b32ff7a1258bc285fe99
 
 LABEL maintainer="Robert Kaussow <mail@thegeeklab.de>"
 LABEL org.opencontainers.image.authors="Robert Kaussow <mail@thegeeklab.de>"