diff --git a/.github/workflows/php-tests.yml b/.github/workflows/php-tests.yml
index d4dcb40..552012c 100644
--- a/.github/workflows/php-tests.yml
+++ b/.github/workflows/php-tests.yml
@@ -40,7 +40,7 @@ jobs:
                 uses: "ergebnis/.github/actions/composer/determine-cache-directory@1.9.3"
 
             -   name: "Cache dependencies installed with composer"
-                uses: "actions/cache@v4.2.3"
+                uses: "actions/cache@0400d5f644dc74513175e3cd8d07132dd4860809" # v4.2.4
                 with:
                     path: "${{ env.COMPOSER_CACHE_DIR }}"
                     key: "php-${{ matrix.php-version }}-composer-${{ matrix.dependencies }}-${{ hashFiles('composer.lock') }}"