diff --git a/.github/workflows/backwards-compatibility.yml b/.github/workflows/backwards-compatibility.yml
index 219b03a..9c4f0ee 100644
--- a/.github/workflows/backwards-compatibility.yml
+++ b/.github/workflows/backwards-compatibility.yml
@@ -11,7 +11,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: "actions/checkout@v3"
+        uses: "actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac" # v4
         with:
           fetch-depth: 0
 
diff --git a/.github/workflows/coding-standards.yml b/.github/workflows/coding-standards.yml
index 178fe9a..1bdc87c 100644
--- a/.github/workflows/coding-standards.yml
+++ b/.github/workflows/coding-standards.yml
@@ -21,7 +21,7 @@ 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/composer-json-lint.yml b/.github/workflows/composer-json-lint.yml
index a7eb473..279bf6d 100644
--- a/.github/workflows/composer-json-lint.yml
+++ b/.github/workflows/composer-json-lint.yml
@@ -21,7 +21,7 @@ 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 b63e123..08a88da 100644
--- a/.github/workflows/mutation-tests.yml
+++ b/.github/workflows/mutation-tests.yml
@@ -21,7 +21,7 @@ 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 86c71cb..d329f2c 100644
--- a/.github/workflows/phpunit.yml
+++ b/.github/workflows/phpunit.yml
@@ -24,7 +24,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: "actions/checkout@v3"
+        uses: "actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac" # v4
 
       - name: "Install PHP"
         uses: "shivammathur/setup-php@v2"
@@ -80,7 +80,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: "actions/checkout@v3"
+        uses: "actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac" # v4
 
       - name: "Install PHP"
         uses: "shivammathur/setup-php@v2"
@@ -124,7 +124,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: "actions/checkout@v3"
+        uses: "actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac" # v4
 
       - name: "Install PHP"
         uses: "shivammathur/setup-php@2.17.0"
diff --git a/.github/workflows/release-on-milestone-closed.yml b/.github/workflows/release-on-milestone-closed.yml
index 1db015b..7ad4e79 100644
--- a/.github/workflows/release-on-milestone-closed.yml
+++ b/.github/workflows/release-on-milestone-closed.yml
@@ -14,7 +14,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: "actions/checkout@v3"
+        uses: "actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac" # v4
 
       - name: "Release"
         uses: "laminas/automatic-releases@v1"
diff --git a/.github/workflows/static-analysis.yml b/.github/workflows/static-analysis.yml
index af4b49d..e07a59f 100644
--- a/.github/workflows/static-analysis.yml
+++ b/.github/workflows/static-analysis.yml
@@ -21,7 +21,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: "actions/checkout@v3"
+        uses: "actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac" # v4
 
       - name: "Install PHP"
         uses: "shivammathur/setup-php@v2"