diff --git a/.github/workflows/cleanup.yml b/.github/workflows/cleanup.yml
index e7a18a25..44451ac2 100644
--- a/.github/workflows/cleanup.yml
+++ b/.github/workflows/cleanup.yml
@@ -13,12 +13,12 @@ jobs:
       pull-requests: write
     steps:
       - name: Checkout Repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           ref: ${{ github.event.pull_request.head.ref }}
           fetch-depth: 0
       - name: Setup Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5
         with:
           python-version: 3.11
       - name: Install Dependencies
diff --git a/.github/workflows/pr_reply1.yml b/.github/workflows/pr_reply1.yml
index 93debf68..f6aa4f3d 100644
--- a/.github/workflows/pr_reply1.yml
+++ b/.github/workflows/pr_reply1.yml
@@ -10,10 +10,10 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3
       with:
         fetch-depth: 0
-    - uses: actions/setup-python@v3
+    - uses: actions/setup-python@3542bca2639a428e1796aaa6a2ffef0c0f575566 # v3
       with:
         python-version: 3.9
     - name: Run script
@@ -22,7 +22,7 @@ jobs:
       run: |
         pip install -Uq ghapi nb_helpers
         python .github/scripts/pr_reply1.py
-    - uses: actions/upload-artifact@v4
+    - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
       with:
         name: pr_comment
         path: modified_colabs.json
\ No newline at end of file
diff --git a/.github/workflows/pr_reply2.yml b/.github/workflows/pr_reply2.yml
index 558077eb..f1e81089 100644
--- a/.github/workflows/pr_reply2.yml
+++ b/.github/workflows/pr_reply2.yml
@@ -13,10 +13,10 @@ jobs:
   download_payload:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3
       with:
         fetch-depth: 0
-    - uses: actions/setup-python@v3
+    - uses: actions/setup-python@3542bca2639a428e1796aaa6a2ffef0c0f575566 # v3
       with:
         python-version: 3.9
     - name: Run script