diff --git a/.github/workflows/composer-diff.yml b/.github/workflows/composer-diff.yml
index 1b6da07..ad374bf 100644
--- a/.github/workflows/composer-diff.yml
+++ b/.github/workflows/composer-diff.yml
@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
         with:
           # Required to make it possible to compare with PR base branch
           fetch-depth: 0
@@ -17,9 +17,9 @@ jobs:
       - name: Generate composer diff
         # To reference the output in comment
         id: composer_diff
-        uses: IonBazan/composer-diff-action@v1
+        uses: IonBazan/composer-diff-action@3140157575f6a67799cc80248ae35f5fb303ab15 # v1
 
-      - uses: marocchino/sticky-pull-request-comment@v2
+      - uses: marocchino/sticky-pull-request-comment@52423e01640425a022ef5fd42c6fb5f633a02728 # v2
         # An empty diff result will break this action.
         if: ${{ steps.composer_diff.outputs.composer_diff_exit_code != 0 }}
         with:
diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index b216bde..025fbe9 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -19,7 +19,7 @@ jobs:
 
     steps:
       - name: Setup PHP
-        uses: shivammathur/setup-php@v2
+        uses: shivammathur/setup-php@9e72090525849c5e82e596468b86eb55e9cc5401 # v2
         with:
           php-version: ${{ matrix.php-versions }}
           extensions: mbstring, intl, fileinfo
@@ -27,14 +27,14 @@ jobs:
           coverage: xdebug
           tools: php-cs-fixer, phpunit:${{ matrix.phpunit-versions }}
 
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
 
       - name: Validate composer.json and composer.lock
         run: composer validate
 
       - name: Cache Composer packages
         id: composer-cache
-        uses: actions/cache@v4
+        uses: actions/cache@1bd1e32a3bdc45362d1e726936510720a7c30a57 # v4
         with:
           path: vendor
           key: ${{ runner.os }}-php-${{ matrix.php-versions }}-${{ hashFiles('**/composer.lock') }}