diff --git a/.github/workflows/cpp-linter.yml b/.github/workflows/cpp-linter.yml
index 2e81205..d3ae869 100644
--- a/.github/workflows/cpp-linter.yml
+++ b/.github/workflows/cpp-linter.yml
@@ -13,7 +13,7 @@ jobs:
   cpp-linter:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3  # v6.0.0
       - uses: cpp-linter/cpp-linter-action@main
         id: linter
         continue-on-error: true
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 542d452..ad92205 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -22,7 +22,7 @@ jobs:
   re-tag:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3  # v6.0.0
       with:
         fetch-depth: 0
         ref: ${{ inputs.ref }}
diff --git a/.github/workflows/self-test.yml b/.github/workflows/self-test.yml
index 67015b2..5c60ebf 100644
--- a/.github/workflows/self-test.yml
+++ b/.github/workflows/self-test.yml
@@ -39,7 +39,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3  # v6.0.0
 
       - name: Cache the build artifacts
         id: cache-build