diff --git a/.github/workflows/site.yml b/.github/workflows/site.yml
index b50ddd2..f7bb296 100644
--- a/.github/workflows/site.yml
+++ b/.github/workflows/site.yml
@@ -10,13 +10,13 @@ jobs:
   deploy:
     runs-on: ubuntu-20.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@ee0669bd1cc54295c223e0bb666b733df41de1c5 # v2
         with:
           submodules: true  # Fetch Hugo themes (true OR recursive)
           fetch-depth: 0    # Fetch all history for .GitInfo and .Lastmod
 
       - name: Setup Hugo
-        uses: peaceiris/actions-hugo@v2
+        uses: peaceiris/actions-hugo@16361eb4acea8698b220b76c0d4e84e1fd22c61d # v2
         with:
           hugo-version: 'latest'
           extended: true
@@ -25,7 +25,7 @@ jobs:
         run: hugo --minify
 
       - name: Deploy
-        uses: peaceiris/actions-gh-pages@v3
+        uses: peaceiris/actions-gh-pages@373f7f263a76c20808c831209c920827a82a2847 # v3
         if: github.ref == 'refs/heads/main'
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}