diff --git a/.github/workflows/cmake.yml b/.github/workflows/cmake.yml
index b597b655..6a545a81 100644
--- a/.github/workflows/cmake.yml
+++ b/.github/workflows/cmake.yml
@@ -19,7 +19,7 @@ jobs:
         gcc: [12]
     runs-on: ${{ matrix.os }}
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938  # v4.2.0
 
     - name: Linux dependencies
       if: startsWith(matrix.os, 'ubuntu')
diff --git a/.github/workflows/open_actions_pr.yml b/.github/workflows/open_actions_pr.yml
index 9562c3e9..999ce51b 100644
--- a/.github/workflows/open_actions_pr.yml
+++ b/.github/workflows/open_actions_pr.yml
@@ -10,6 +10,6 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Label PR
-      uses: actions/labeler@v5
+      uses: actions/labeler@8558fd74291d67161a8a78ce36a881fa63b766a9  # v5.0.0
       with:
         repo-token: "${{ secrets.GITHUB_TOKEN }}"