diff --git a/.github/workflows/checks.yml b/.github/workflows/checks.yml
index c0e21f6b..0549a131 100644
--- a/.github/workflows/checks.yml
+++ b/.github/workflows/checks.yml
@@ -10,7 +10,7 @@ jobs:
   solhint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - uses: actions/setup-node@v3
         with:
           node-version: 16
@@ -22,7 +22,7 @@ jobs:
   codespell:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - name: Run CodeSpell
         uses: codespell-project/actions-codespell@v2.0
         with:
@@ -33,7 +33,7 @@ jobs:
   upgradeable:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - uses: actions/setup-node@v3
         with:
           node-version: 16
@@ -45,7 +45,7 @@ jobs:
   contract-storage-layout:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
         with:
           submodules: recursive
       - uses: actions/setup-node@v3
@@ -65,7 +65,7 @@ jobs:
   mythril:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - uses: actions/setup-node@v3
         with:
           node-version: 16
@@ -80,7 +80,7 @@ jobs:
       contents: read
       security-events: write
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - uses: actions/setup-node@v3
         with:
           node-version: 16
diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index 5f7e0fd2..68097331 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -10,7 +10,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
         with:
           submodules: recursive
 
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 5abbf40c..90785c86 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -10,7 +10,7 @@ jobs:
   run-linters:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - uses: actions/setup-node@v3
         with:
           node-version: 16
diff --git a/.github/workflows/mythx.yml b/.github/workflows/mythx.yml
index 569b1f23..fff6136c 100644
--- a/.github/workflows/mythx.yml
+++ b/.github/workflows/mythx.yml
@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
 
       - name: Set up node
         uses: actions/setup-node@v3
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index a1f1e37b..b4eae708 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
         with:
           submodules: recursive
       - uses: actions/setup-node@v3