diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 5f33dae..464e23c 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -8,7 +8,7 @@ jobs:
     name: Build distribution
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
       - name: Set up Python
         uses: actions/setup-python@v6
         with:
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 0ea9f47..0b56cc9 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -5,7 +5,7 @@ jobs:
     name: pip install
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
       - name: Set up Python
         uses: actions/setup-python@v6
         with:
@@ -16,7 +16,7 @@ jobs:
     name: twine check
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
       - name: Set up Python
         uses: actions/setup-python@v6
         with:
@@ -29,7 +29,7 @@ jobs:
     name: black
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
       - name: Set up Python
         uses: actions/setup-python@v6
         with:
@@ -44,7 +44,7 @@ jobs:
       matrix:
         python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
         with:
           lfs: true
       - name: Set up Python ${{ matrix.python-version }}
@@ -59,7 +59,7 @@ jobs:
     name: Run Benchmark on Python 3.13
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
         with:
           lfs: true
       - name: Set up Python