diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index da3ad72..90604f1 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -13,22 +13,22 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
 
       - name: Compute docker tags
         id: docker_meta
-        uses: crazy-max/ghaction-docker-meta@v5
+        uses: crazy-max/ghaction-docker-meta@369eb591f429131d6889c46b94e711f089e6ca96 # v5
         with:
           images: orangecloudfoundry/create-bosh-release-action
 
       - name: Login to DockerHub
-        uses: docker/login-action@v3
+        uses: docker/login-action@9780b0c442fbb1117ed29e0efdff1e18412f7567 # v3
         with:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
       - name: Publish to DockerHub
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@67a2d409c0a876cbe6b11854e3e25193efe4e62d # v6
         with:
           push: true
           tags: ${{ steps.docker_meta.outputs.tags }}
diff --git a/.github/workflows/on-commit.yml b/.github/workflows/on-commit.yml
index 505a838..636583c 100644
--- a/.github/workflows/on-commit.yml
+++ b/.github/workflows/on-commit.yml
@@ -12,13 +12,13 @@ jobs:
     steps:
       - name: Checkout repository
         id: checkout_repo
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
         with:
           fetch-depth: 0
           path: ./create-bosh-release-action
       - name: Checkout repository test repo
         id: checkout_test_repo
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
         with:
           repository: 'orange-cloudfoundry/create-bosh-release-action-test-boshrelease'
           fetch-depth: 0
diff --git a/Dockerfile b/Dockerfile
index 28d592f..c126529 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ruby:alpine
+FROM ruby:alpine@sha256:e5c30595c6a322bc3fbaacd5e35d698a6b9e6d1079ab0af09ffe52f5816aec3b
 
 RUN apk add git curl jq bash