diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index f62b4e8..039d870 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -13,7 +13,7 @@ jobs:
         python-version: [3.8, 3.9, "3.10", 3.11]
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v4
       with:
@@ -32,7 +32,7 @@ jobs:
     runs-on: "ubuntu-latest"
     needs: [test]
     steps:
-      - uses: "actions/checkout@v3"
+      - uses: "actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac" # v4
       - uses: "actions/setup-python@v4"
         with:
           python-version: "3.9"