diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 4809bfa..0a379fd 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,7 +1,7 @@
-image: "docker:latest"
+image: "docker:latest@sha256:7d85d0eda291f1a7ab6df4a9d1802b5ad4cf9145a088bd11188c78dcb5c7392b"
 
 services:
-  - "docker:dind"
+  - "docker:dind@sha256:7d85d0eda291f1a7ab6df4a9d1802b5ad4cf9145a088bd11188c78dcb5c7392b"
 
 before_script:
   - "docker login -u \"$CI_REGISTRY_USER\" -p \"$CI_REGISTRY_PASSWORD\" $CI_REGISTRY"
diff --git a/Dockerfile b/Dockerfile
index ee8a96c..4cd85a5 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM python:3.9-alpine
+FROM python:3.9-alpine@sha256:c99b6eb43b3ac4d750db3d6e8b22268d5ea9a99deead7218ce3deda7f2ca029c
 LABEL maintainer="Julien Cabillot <dockerimages@cabillot.eu>"
 
 ARG CLI_VERSION=1.16.148