diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index 652c52c..72169ee 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -18,10 +18,10 @@ jobs:
   build-docs:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405
         with:
           python-version: "3.10"
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd
       - name: Install PyVMCON with docs dependencies
         run: pip install '.[docs]'
       - name: Install pandoc
@@ -34,11 +34,11 @@ jobs:
           make html
           cd ..
       - name: Setup pages
-        uses: actions/configure-pages@v5
+        uses: actions/configure-pages@983d7736d9b0ae728b81ab479565c72886d7745b
       - name: Upload static HTML
-        uses: actions/upload-pages-artifact@v3
+        uses: actions/upload-pages-artifact@7b1f4a764d45c48632c6b24a0339c27f5614fb0b
         with:
           path: "docs/build/html/"
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v4
+        uses: actions/deploy-pages@d6db90164ac5ed86f2b6aed7e0febac5b3c0c03e
diff --git a/.github/workflows/pypi.yml b/.github/workflows/pypi.yml
index 11381f9..8f0867d 100644
--- a/.github/workflows/pypi.yml
+++ b/.github/workflows/pypi.yml
@@ -12,14 +12,14 @@ jobs:
       contents: read
       id-token: write
     steps:
-    - uses: actions/checkout@v4
-    - name: Set up Python
-      uses: actions/setup-python@v5
-      with:
-        python-version: "3.x"
-    - name: Install pypa/build
-      run: python3 -m pip install build
-    - name: Build a binary wheel and a source tarball
-      run: python3 -m build --sdist --wheel --outdir dist/ .
-    - name: Publish PyVMCON to Test PyPI
-      uses: pypa/gh-action-pypi-publish@release/v1
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd
+      - name: Set up Python
+        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405
+        with:
+          python-version: "3.x"
+      - name: Install pypa/build
+        run: python3 -m pip install build
+      - name: Build a binary wheel and a source tarball
+        run: python3 -m build --sdist --wheel --outdir dist/ .
+      - name: Publish PyVMCON to Test PyPI
+        uses: pypa/gh-action-pypi-publish@release/v1
diff --git a/.github/workflows/quality.yml b/.github/workflows/quality.yml
index 407c4a8..9725acd 100644
--- a/.github/workflows/quality.yml
+++ b/.github/workflows/quality.yml
@@ -12,10 +12,10 @@ jobs:
   quality_assure_pyvmcon:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405
         with:
           python-version: "3.10"
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd
       - name: Install pre-commit
         run: pip install pre-commit
       - name: Run pre-commit
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 3e7eecc..825b299 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -16,10 +16,10 @@ jobs:
         python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405
         with:
           python-version: ${{ matrix.python-version }}
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd
       - name: Install pytest
         run: pip install pytest
       - name: Install PyVMCON