diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d5ca52c..d98a763 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - name: Set up Python
         uses: actions/setup-python@v4
         with:
diff --git a/.github/workflows/container_build.yml b/.github/workflows/container_build.yml
index 7026d6c..fb6a121 100644
--- a/.github/workflows/container_build.yml
+++ b/.github/workflows/container_build.yml
@@ -28,7 +28,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
 
       - name: Log in to the Container registry
         uses: docker/login-action@v2