diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c3a1485..fd81d0a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,9 +12,9 @@ jobs:
   build-and-test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@ee0669bd1cc54295c223e0bb666b733df41de1c5 # v2
 
-      - uses: actions/setup-python@v2
+      - uses: actions/setup-python@e9aba2c848f5ebd159c070c61ea2c4e2b122355e # v2
         with:
           python-version: 3.9
 
diff --git a/.github/workflows/doc.yml b/.github/workflows/doc.yml
index f27242c..d212a79 100644
--- a/.github/workflows/doc.yml
+++ b/.github/workflows/doc.yml
@@ -10,9 +10,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout main
-        uses: actions/checkout@v2
+        uses: actions/checkout@ee0669bd1cc54295c223e0bb666b733df41de1c5 # v2
 
-      - uses: actions/setup-python@v2
+      - uses: actions/setup-python@e9aba2c848f5ebd159c070c61ea2c4e2b122355e # v2
         with:
           python-version: 3.9