diff --git a/.github/workflows/base120.yml b/.github/workflows/base120.yml
index 7164edf..5e70b6b 100644
--- a/.github/workflows/base120.yml
+++ b/.github/workflows/base120.yml
@@ -16,7 +16,7 @@ jobs:
   mirror-guard:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v6.0.3
 
       - name: Enforce mirror corpus compliance
         run: |
@@ -27,7 +27,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v6.0.3
 
       - name: Set up Python
         uses: actions/setup-python@v6
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4f69e61..2decf4c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,7 +13,7 @@ jobs:
       matrix:
         python-version: ["3.11", "3.12"]
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
 
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v5
diff --git a/.github/workflows/guardrails.yml b/.github/workflows/guardrails.yml
index 6c4bac6..a086d35 100644
--- a/.github/workflows/guardrails.yml
+++ b/.github/workflows/guardrails.yml
@@ -13,7 +13,7 @@ jobs:
   corpus:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v6.0.3
       - uses: actions/setup-python@v6
         with:
           python-version: "3.13"
diff --git a/.github/workflows/mirror-conformance.yml b/.github/workflows/mirror-conformance.yml
index f62e246..38b992a 100644
--- a/.github/workflows/mirror-conformance.yml
+++ b/.github/workflows/mirror-conformance.yml
@@ -40,12 +40,12 @@ jobs:
     
     steps:
       - name: Checkout mirror repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v6.0.3
         with:
           path: mirror-repo
       
       - name: Checkout canonical Base120 repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v6.0.3
         with:
           repository: hummbl-dev/base120
           ref: main