diff --git a/.github/workflows/code-style.yml b/.github/workflows/code-style.yml
index 9566392..24d6f2c 100644
--- a/.github/workflows/code-style.yml
+++ b/.github/workflows/code-style.yml
@@ -27,7 +27,7 @@ jobs:
                   git config --global core.eol lf
 
             - 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 7a8547e..356dbef 100644
--- a/.github/workflows/mutation-tests.yml
+++ b/.github/workflows/mutation-tests.yml
@@ -29,7 +29,7 @@ jobs:
                   git config --global core.eol lf
 
             - name: Checkout
-              uses: actions/checkout@v3
+              uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
 
             - name: Install PHP
               uses: shivammathur/setup-php@v2
diff --git a/.github/workflows/prettier.yml b/.github/workflows/prettier.yml
index 1b76445..0ff118a 100644
--- a/.github/workflows/prettier.yml
+++ b/.github/workflows/prettier.yml
@@ -11,7 +11,7 @@ jobs:
 
         steps:
             - name: Checkout
-              uses: actions/checkout@v3
+              uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
 
             - name: Install the Nix package manager
               uses: cachix/install-nix-action@v22
diff --git a/.github/workflows/release.yaml b/.github/workflows/release.yaml
index 3c87dc2..6f17689 100644
--- a/.github/workflows/release.yaml
+++ b/.github/workflows/release.yaml
@@ -15,7 +15,7 @@ jobs:
 
         steps:
             - name: Checkout
-              uses: actions/checkout@v3
+              uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
 
             - name: Determine tag
               id: tag_name
diff --git a/.github/workflows/static-analysis.yml b/.github/workflows/static-analysis.yml
index a55bc6f..e39b8e6 100644
--- a/.github/workflows/static-analysis.yml
+++ b/.github/workflows/static-analysis.yml
@@ -27,7 +27,7 @@ jobs:
                   git config --global core.eol lf
 
             - name: Checkout
-              uses: actions/checkout@v3
+              uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
 
             - name: Install PHP
               uses: shivammathur/setup-php@v2
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index b0e2087..3cf22dc 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -17,7 +17,7 @@ jobs:
         outputs:
             version: ${{ steps.supported-versions-matrix.outputs.version }}
         steps:
-            - uses: actions/checkout@v3
+            - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
             - id: supported-versions-matrix
               uses: WyriHaximus/github-action-composer-php-versions-in-range@v1
     tests:
@@ -37,7 +37,7 @@ jobs:
                   git config --global core.eol lf
 
             - name: Checkout
-              uses: actions/checkout@v3
+              uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
 
             - name: Install PHP
               uses: shivammathur/setup-php@v2