diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 41a9e33..e6d7f23 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -18,7 +18,7 @@ jobs:
     runs-on: ${{ matrix.os }}
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@ee0669bd1cc54295c223e0bb666b733df41de1c5 # v2.7.0
       - name: Install valgrind
         run: |
           if [ "$RUNNER_OS" == "Linux" ]; then
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index d7816ff..5a68548 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -7,8 +7,8 @@ jobs:
   create-release:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - uses: taiki-e/create-gh-release-action@v1
+      - uses: actions/checkout@ee0669bd1cc54295c223e0bb666b733df41de1c5 # v2.7.0
+      - uses: taiki-e/create-gh-release-action@c5baa0b5dc700cf06439d87935e130220a6882d9 # v1.9.3
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
   upload-assets:
@@ -23,8 +23,8 @@ jobs:
             os: macos-latest
     runs-on: ${{ matrix.os || 'ubuntu-latest'}}
     steps:
-      - uses: actions/checkout@v2
-      - uses: taiki-e/upload-rust-binary-action@v1
+      - uses: actions/checkout@ee0669bd1cc54295c223e0bb666b733df41de1c5 # v2.7.0
+      - uses: taiki-e/upload-rust-binary-action@381995c84a8e242b8736ec80211c563d7bd07ce7 # v1.28.1
         with:
           bin: sirun
           target: ${{ matrix.target }}