diff --git a/.github/workflows/ghcr.yml b/.github/workflows/ghcr.yml
index 33452e9..a790632 100644
--- a/.github/workflows/ghcr.yml
+++ b/.github/workflows/ghcr.yml
@@ -27,7 +27,7 @@ jobs:
       contents: read
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
 
       - name: Build image
         run: docker build . --file Dockerfile --tag $IMAGE_NAME --label "runnumber=${GITHUB_RUN_ID}"
diff --git a/.github/workflows/pypi.yml b/.github/workflows/pypi.yml
index 759fd00..f331a47 100644
--- a/.github/workflows/pypi.yml
+++ b/.github/workflows/pypi.yml
@@ -9,9 +9,9 @@ jobs:
 
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
       - name: Setup Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
         with:
           python-version: '3.11'
       - name: Install dependencies
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 9fb4008..15e7ec8 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -8,7 +8,7 @@ jobs:
   tests:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
       - name: Set UID
         run: echo "UID=$(id --user)" > .env
       - name: Build the containers