diff --git a/.github/workflows/coding-standard.yml b/.github/workflows/coding-standard.yml
index c4fb3c6..f018b54 100644
--- a/.github/workflows/coding-standard.yml
+++ b/.github/workflows/coding-standard.yml
@@ -26,7 +26,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: actions/checkout@v3
+        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
 
       - name: "Install PHP"
         uses: "shivammathur/setup-php@v2"
diff --git a/.github/workflows/mutation-tests.yml b/.github/workflows/mutation-tests.yml
index edda6c1..aae5b67 100644
--- a/.github/workflows/mutation-tests.yml
+++ b/.github/workflows/mutation-tests.yml
@@ -26,7 +26,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: actions/checkout@v3
+        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
 
       - name: "Install PHP"
         uses: "shivammathur/setup-php@v2"
diff --git a/.github/workflows/phpstan.yml b/.github/workflows/phpstan.yml
index 27dd456..c24e4ce 100644
--- a/.github/workflows/phpstan.yml
+++ b/.github/workflows/phpstan.yml
@@ -26,7 +26,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: actions/checkout@v3
+        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
 
       - name: "Install PHP"
         uses: "shivammathur/setup-php@v2"
diff --git a/.github/workflows/phpunit.yml b/.github/workflows/phpunit.yml
index 4dcdb85..1a3b2c0 100644
--- a/.github/workflows/phpunit.yml
+++ b/.github/workflows/phpunit.yml
@@ -35,7 +35,7 @@ jobs:
             operating-system: "windows-latest"
     steps:
       - name: "Checkout"
-        uses: actions/checkout@v3
+        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
 
       - name: "Install PHP"
         uses: "shivammathur/setup-php@v2"
diff --git a/.github/workflows/psalm.yml b/.github/workflows/psalm.yml
index 524fba0..c4bdf41 100644
--- a/.github/workflows/psalm.yml
+++ b/.github/workflows/psalm.yml
@@ -26,7 +26,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: actions/checkout@v3
+        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
 
       - name: "Install PHP"
         uses: "shivammathur/setup-php@v2"
diff --git a/.github/workflows/release-on-milestone-closed-triggering-release-event.yml b/.github/workflows/release-on-milestone-closed-triggering-release-event.yml
index 9388753..d031c17 100644
--- a/.github/workflows/release-on-milestone-closed-triggering-release-event.yml
+++ b/.github/workflows/release-on-milestone-closed-triggering-release-event.yml
@@ -18,7 +18,7 @@ jobs:
 
         steps:
             - name: "Checkout"
-              uses: actions/checkout@v3
+              uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
 
             - name: "Release"
               uses: "laminas/automatic-releases@v1"