diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e97b412..7ece2f4 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -10,7 +10,7 @@ jobs:
   lint-and-security:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
@@ -32,7 +32,7 @@ jobs:
   tests-and-coverage:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       
       - name: Set up Python
         uses: actions/setup-python@v5
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 9839890..3a8b4db 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -22,7 +22,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v4
+      uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
 
     - name: Initialize CodeQL
       uses: github/codeql-action/init@v3