diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index a7d0f497..0b02647b 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -55,7 +55,7 @@ jobs:
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
-      uses: github/codeql-action/init@v3
+      uses: github/codeql-action/init@28deaeda66b76a05916b6923827895f2b14ab387 # v3
       with:
         languages: ${{ matrix.language }}
         build-mode: none
@@ -71,6 +71,6 @@ jobs:
         pip install -e .
 
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v3
+      uses: github/codeql-action/analyze@28deaeda66b76a05916b6923827895f2b14ab387 # v3
       with:
         category: "/language:${{matrix.language}}"
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 13f769ec..b0cd6f66 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -79,14 +79,14 @@ jobs:
           name: all-dist-${{ github.run_id }}
           path: dist/
       - name: Publish package distributions to TestPyPI
-        uses: pypa/gh-action-pypi-publish@release/v1
+        uses: pypa/gh-action-pypi-publish@76f52bc884231f62b9a034ebfe128415bbaabdfc # release/v1
         with:
           repository-url: https://test.pypi.org/legacy/
           skip-existing: true
           attestations: ${{ env.DRY_RUN }}
       - name: Publish package distributions to PyPI
         if: startsWith(env.DRY_RUN, 'false')
-        uses: pypa/gh-action-pypi-publish@release/v1
+        uses: pypa/gh-action-pypi-publish@76f52bc884231f62b9a034ebfe128415bbaabdfc # release/v1
 
   post-publish:
     needs: [publish]
diff --git a/.github/workflows/test-python.yml b/.github/workflows/test-python.yml
index 353898ff..39cb424d 100644
--- a/.github/workflows/test-python.yml
+++ b/.github/workflows/test-python.yml
@@ -83,7 +83,7 @@ jobs:
       - name: Run linkcheck
         run: tox -m linkcheck
       - name: Start MongoDB
-        uses: supercharge/mongodb-github-action@1.12.0
+        uses: supercharge/mongodb-github-action@90004df786821b6308fb02299e5835d0dae05d0d # 1.12.0
         with:
           mongodb-version: 5.0
       - name: Run doctest
diff --git a/.github/workflows/zizmor.yml b/.github/workflows/zizmor.yml
index 92bd4fb4..e0dc0fb2 100644
--- a/.github/workflows/zizmor.yml
+++ b/.github/workflows/zizmor.yml
@@ -18,7 +18,7 @@ jobs:
         with:
           persist-credentials: false
       - name: Setup Rust
-        uses: actions-rust-lang/setup-rust-toolchain@v1
+        uses: actions-rust-lang/setup-rust-toolchain@9d7e65c320fdb52dcd45ffaa68deb6c02c8754d9 # v1
       - name: Get zizmor
         run: cargo install zizmor
       - name: Run zizmor
@@ -26,7 +26,7 @@ jobs:
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       - name: Upload SARIF file
-        uses: github/codeql-action/upload-sarif@v3
+        uses: github/codeql-action/upload-sarif@28deaeda66b76a05916b6923827895f2b14ab387 # v3
         with:
           sarif_file: results.sarif
           category: zizmor