diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
index c3012098..94731799 100644
--- a/.github/workflows/coverage.yml
+++ b/.github/workflows/coverage.yml
@@ -12,7 +12,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
     - name: Set up Python 3.9
       uses: actions/setup-python@v4
       with:
diff --git a/.github/workflows/pythonapp.yml b/.github/workflows/pythonapp.yml
index ce2282fa..c99a1082 100644
--- a/.github/workflows/pythonapp.yml
+++ b/.github/workflows/pythonapp.yml
@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
     - name: Set up Python 3.9
       uses: actions/setup-python@v4
       with: