diff --git a/.github/workflows/recibo_python_test.yaml b/.github/workflows/recibo_python_test.yaml
index d1b52dc..f93b591 100644
--- a/.github/workflows/recibo_python_test.yaml
+++ b/.github/workflows/recibo_python_test.yaml
@@ -33,7 +33,7 @@ jobs:
 
     steps:
       - name: Check out repository code
-        uses: actions/checkout@v4
+        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
 
       - name: Update submodules
         run: git submodule update --init --recursive
diff --git a/.github/workflows/recibo_test.yaml b/.github/workflows/recibo_test.yaml
index d36f647..22e3a5a 100644
--- a/.github/workflows/recibo_test.yaml
+++ b/.github/workflows/recibo_test.yaml
@@ -32,7 +32,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out repository code
-        uses: actions/checkout@v4
+        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
 
       - name: Update submodules
         run: git submodule update --init --recursive