diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 1d879e9..d0e82ab 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -19,10 +19,10 @@ jobs:
         php: ['8.1', '8.2', '8.3', '8.4']
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
       - name: Setup PHP
-        uses: shivammathur/setup-php@v2
+        uses: shivammathur/setup-php@accd6127cb78bee3e8082180cb391013d204ef9f # v2
         with:
           php-version: ${{ matrix.php }}
           extensions: json, mbstring
@@ -34,7 +34,7 @@ jobs:
 
       - name: Cache Composer packages
         id: composer-cache
-        uses: actions/cache@v4
+        uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
         with:
           path: vendor
           key: ${{ runner.os }}-php-${{ matrix.php }}-${{ hashFiles('**/composer.lock') }}