diff --git a/.github/workflows/bundler_audit.yml b/.github/workflows/bundler_audit.yml
index 4a49624..29e3157 100644
--- a/.github/workflows/bundler_audit.yml
+++ b/.github/workflows/bundler_audit.yml
@@ -11,7 +11,7 @@ jobs:
       matrix:
         ruby-version: ["3.3", "3.4"]
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with:
diff --git a/.github/workflows/publish_gem.yml b/.github/workflows/publish_gem.yml
index 4275292..6e64665 100644
--- a/.github/workflows/publish_gem.yml
+++ b/.github/workflows/publish_gem.yml
@@ -11,7 +11,7 @@ jobs:
       packages: write
     steps:
       - name: Check out repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
 
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
diff --git a/.github/workflows/rspec.yml b/.github/workflows/rspec.yml
index 87c56d6..8dc8fa9 100644
--- a/.github/workflows/rspec.yml
+++ b/.github/workflows/rspec.yml
@@ -16,7 +16,7 @@ jobs:
       matrix:
         ruby-version: ["3.3", "3.4"]
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
       - name: Set up Ruby
         # To automatically get bug fixes and new Ruby versions for ruby/setup-ruby
         uses: ruby/setup-ruby@v1