diff --git a/.github/workflows/docker-image.yml b/.github/workflows/docker-image.yml
index 88813bd..a706389 100644
--- a/.github/workflows/docker-image.yml
+++ b/.github/workflows/docker-image.yml
@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6
     - name: Login to GHCR.io
       run: docker login --username guerda --password ${{ secrets.PAT }} ghcr.io
     - name: Build the Docker image
diff --git a/.github/workflows/python-app.yml b/.github/workflows/python-app.yml
index 7d9bab6..e4dafc0 100644
--- a/.github/workflows/python-app.yml
+++ b/.github/workflows/python-app.yml
@@ -18,9 +18,9 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6
     - name: Set up Python 3.13
-      uses: actions/setup-python@v6
+      uses: actions/setup-python@83679a892e2d95755f2dac6acb0bfd1e9ac5d548 # v6
       with:
         python-version: "3.13"
     - name: Install dependencies
diff --git a/Dockerfile b/Dockerfile
index 6820595..cea86bd 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,6 @@
-FROM python:3.13-slim
+FROM python:3.13-slim@sha256:1f3781f578e17958f55ada96c0a827bf279a11e10d6a458ecb8bde667afbb669
 # Install uv.
-COPY --from=ghcr.io/astral-sh/uv:latest /uv /uvx /bin/
+COPY --from=ghcr.io/astral-sh/uv:latest@sha256:15f68a476b768083505fe1dbfcc998344d0135f0ca1b8465c4760b323904f05a /uv /uvx /bin/
 
 WORKDIR /app
 COPY ./uv.lock ./pyproject.toml /app/