diff --git a/.github/workflows/add-issue-header.yml b/.github/workflows/add-issue-header.yml
index c404bc519300e2..8a8571eedd1c77 100644
--- a/.github/workflows/add-issue-header.yml
+++ b/.github/workflows/add-issue-header.yml
@@ -20,7 +20,7 @@ jobs:
       issues: write
     timeout-minutes: 5
     steps:
-      - uses: actions/github-script@v8
+      - uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8.0.0
         with:
           # language=JavaScript
           script: |
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 055fa7c0cdb7cc..d88a4f1b0b75a6 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -55,10 +55,10 @@ jobs:
     needs: build-context
     if: needs.build-context.outputs.run-tests == 'true'
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: '3.x'
       - name: Install dependencies
@@ -89,7 +89,7 @@ jobs:
         if: ${{ failure() && steps.check.conclusion == 'failure' }}
         run: |
           make regen-abidump
-      - uses: actions/upload-artifact@v6
+      - uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
         name: Publish updated ABI files
         if: ${{ failure() && steps.check.conclusion == 'failure' }}
         with:
@@ -111,7 +111,7 @@ jobs:
         run: |
           apt update && apt install git -yq
           git config --global --add safe.directory "$GITHUB_WORKSPACE"
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           fetch-depth: 1
           persist-credentials: false
@@ -148,10 +148,10 @@ jobs:
     needs: build-context
     if: needs.build-context.outputs.run-tests == 'true'
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: '3.x'
       - name: Runner image version
@@ -316,7 +316,7 @@ jobs:
       SSLLIB_DIR: ${{ github.workspace }}/multissl/${{ matrix.ssllib.name }}/${{ matrix.ssllib.version }}
       LD_LIBRARY_PATH: ${{ github.workspace }}/multissl/${{ matrix.ssllib.name }}/${{ matrix.ssllib.version }}/lib
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       with:
         persist-credentials: false
     - name: Runner image version
@@ -327,7 +327,7 @@ jobs:
       run: sudo ./.github/workflows/posix-deps-apt.sh
     - name: 'Restore SSL library build'
       id: cache-ssl-lib
-      uses: actions/cache@v5
+      uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
       with:
         path: ./multissl/${{ matrix.ssllib.name }}/${{ matrix.ssllib.version }}
         key: ${{ matrix.os }}-multissl-${{ matrix.ssllib.name }}-${{ matrix.ssllib.version }}
@@ -375,7 +375,7 @@ jobs:
 
     runs-on: ${{ matrix.runs-on }}
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
       - name: Build and test
@@ -388,7 +388,7 @@ jobs:
     timeout-minutes: 60
     runs-on: macos-14
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
 
@@ -426,7 +426,7 @@ jobs:
       OPENSSL_VER: 3.0.18
       PYTHONSTRICTEXTENSIONBUILD: 1
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       with:
         persist-credentials: false
     - name: Register gcc problem matcher
@@ -440,7 +440,7 @@ jobs:
         echo "LD_LIBRARY_PATH=${GITHUB_WORKSPACE}/multissl/openssl/${OPENSSL_VER}/lib" >> "$GITHUB_ENV"
     - name: 'Restore OpenSSL build'
       id: cache-openssl
-      uses: actions/cache@v5
+      uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
       with:
         path: ./multissl/openssl/${{ env.OPENSSL_VER }}
         key: ${{ runner.os }}-multissl-openssl-${{ env.OPENSSL_VER }}
@@ -487,7 +487,7 @@ jobs:
         ./python -m venv "$VENV_LOC" && "$VENV_PYTHON" -m pip install -r "${GITHUB_WORKSPACE}/Tools/requirements-hypothesis.txt"
     - name: 'Restore Hypothesis database'
       id: cache-hypothesis-database
-      uses: actions/cache@v5
+      uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
       with:
         path: ${{ env.CPYTHON_BUILDDIR }}/.hypothesis/
         key: hypothesis-database-${{ github.head_ref || github.run_id }}
@@ -514,7 +514,7 @@ jobs:
           -x test_subprocess \
           -x test_signal \
           -x test_sysconfig
-    - uses: actions/upload-artifact@v6
+    - uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
       if: always()
       with:
         name: hypothesis-example-db
@@ -535,7 +535,7 @@ jobs:
       PYTHONSTRICTEXTENSIONBUILD: 1
       ASAN_OPTIONS: detect_leaks=0:allocator_may_return_null=1:handle_segv=0
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       with:
         persist-credentials: false
     - name: Runner image version
@@ -545,7 +545,7 @@ jobs:
     - name: Install dependencies
       run: sudo ./.github/workflows/posix-deps-apt.sh
     - name: Set up GCC-10 for ASAN
-      uses: egor-tensin/setup-gcc@v2
+      uses: egor-tensin/setup-gcc@a2861a8b8538f49cf2850980acccf6b05a1b2ae4 # v2.0
       with:
         version: 10
     - name: Configure OpenSSL env vars
@@ -555,7 +555,7 @@ jobs:
         echo "LD_LIBRARY_PATH=${GITHUB_WORKSPACE}/multissl/openssl/${OPENSSL_VER}/lib" >> "$GITHUB_ENV"
     - name: 'Restore OpenSSL build'
       id: cache-openssl
-      uses: actions/cache@v5
+      uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
       with:
         path: ./multissl/openssl/${{ env.OPENSSL_VER }}
         key: ${{ matrix.os }}-multissl-openssl-${{ env.OPENSSL_VER }}
@@ -602,7 +602,7 @@ jobs:
     needs: build-context
     if: needs.build-context.outputs.run-ubuntu == 'true'
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
       - name: Runner image version
diff --git a/.github/workflows/documentation-links.yml b/.github/workflows/documentation-links.yml
index a09a30587b35eb..19314dd0c889b0 100644
--- a/.github/workflows/documentation-links.yml
+++ b/.github/workflows/documentation-links.yml
@@ -22,7 +22,7 @@ jobs:
     timeout-minutes: 5
 
     steps:
-      - uses: readthedocs/actions/preview@v1
+      - uses: readthedocs/actions/preview@b8bba1484329bda1a3abe986df7ebc80a8950333 # v1.5
         with:
           project-slug: "cpython-previews"
           single-version: "true"
diff --git a/.github/workflows/jit.yml b/.github/workflows/jit.yml
index 81db07fffa5eeb..c148c55b623f69 100644
--- a/.github/workflows/jit.yml
+++ b/.github/workflows/jit.yml
@@ -29,7 +29,7 @@ jobs:
     runs-on: ubuntu-24.04
     timeout-minutes: 60
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
       - name: Build tier two interpreter
@@ -66,10 +66,10 @@ jobs:
             architecture: ARM64
             runner: windows-11-arm
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: '3.11'
       # PCbuild downloads LLVM automatically:
@@ -100,10 +100,10 @@ jobs:
           - target: aarch64-apple-darwin/clang
             runner: macos-26
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: '3.11'
       - name: Install LLVM
@@ -143,10 +143,10 @@ jobs:
           - target: aarch64-unknown-linux-gnu/gcc
             runner: ubuntu-24.04-arm
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: '3.11'
       - name: Build
@@ -177,10 +177,10 @@ jobs:
             use_clang: true
             run_tests: false
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: '3.11'
       - name: Build
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 0ded53b00da0ef..e9a4eb2b0808cb 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -19,7 +19,7 @@ jobs:
     timeout-minutes: 10
 
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
-      - uses: j178/prek-action@v1
+      - uses: j178/prek-action@0bb87d7f00b0c99306c8bcb8b8beba1eb581c037 # v1.1.1
diff --git a/.github/workflows/mypy.yml b/.github/workflows/mypy.yml
index c9c457110573a1..ae2095690b2d8a 100644
--- a/.github/workflows/mypy.yml
+++ b/.github/workflows/mypy.yml
@@ -64,10 +64,10 @@ jobs:
           "Tools/peg_generator",
         ]
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: "3.13"
           cache: pip
diff --git a/.github/workflows/new-bugs-announce-notifier.yml b/.github/workflows/new-bugs-announce-notifier.yml
index b25750f0897de2..13e1fdb9c0b985 100644
--- a/.github/workflows/new-bugs-announce-notifier.yml
+++ b/.github/workflows/new-bugs-announce-notifier.yml
@@ -13,12 +13,12 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 10
     steps:
-      - uses: actions/setup-node@v6
+      - uses: actions/setup-node@53b83947a5a98c8d113130e565377fae1a50d02f # v6.3.0
         with:
           node-version: 20
       - run: npm install mailgun.js form-data
       - name: Send notification
-        uses: actions/github-script@v8
+        uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8.0.0
         env:
           MAILGUN_API_KEY: ${{ secrets.MAILGUN_PYTHON_ORG_MAILGUN_KEY }}
         with:
diff --git a/.github/workflows/project-updater.yml b/.github/workflows/project-updater.yml
index 82b23019cb3d96..710424a28f2824 100644
--- a/.github/workflows/project-updater.yml
+++ b/.github/workflows/project-updater.yml
@@ -24,7 +24,7 @@ jobs:
           - { project: 32, label: sprint }
 
     steps:
-      - uses: actions/add-to-project@v1.0.2
+      - uses: actions/add-to-project@244f685bbc3b7adfa8466e08b698b5577571133e # v1.0.2
         with:
           project-url: https://github.com/orgs/python/projects/${{ matrix.project }}
           github-token: ${{ secrets.ADD_TO_PROJECT_PAT }}
diff --git a/.github/workflows/require-pr-label.yml b/.github/workflows/require-pr-label.yml
index 7e534c58c798d1..94cb219aeeeb1f 100644
--- a/.github/workflows/require-pr-label.yml
+++ b/.github/workflows/require-pr-label.yml
@@ -15,7 +15,7 @@ jobs:
 
     steps:
       - name: Check there's no DO-NOT-MERGE
-        uses: mheap/github-action-required-labels@v5
+        uses: mheap/github-action-required-labels@0ac283b4e65c1fb28ce6079dea5546ceca98ccbe # v5.5.2
         with:
           mode: exactly
           count: 0
@@ -33,7 +33,7 @@ jobs:
     steps:
       # Check that the PR is not awaiting changes from the author due to previous review.
       - name: Check there's no required changes
-        uses: mheap/github-action-required-labels@v5
+        uses: mheap/github-action-required-labels@0ac283b4e65c1fb28ce6079dea5546ceca98ccbe # v5.5.2
         with:
           mode: exactly
           count: 0
@@ -42,7 +42,7 @@ jobs:
             awaiting change review
       - id: is-feature
         name: Check whether this PR is a feature (contains a "type-feature" label)
-        uses: mheap/github-action-required-labels@v5
+        uses: mheap/github-action-required-labels@0ac283b4e65c1fb28ce6079dea5546ceca98ccbe # v5.5.2
         with:
           mode: exactly
           count: 1
@@ -53,7 +53,7 @@ jobs:
       - id: awaiting-merge
         if: steps.is-feature.outputs.status == 'success'
         name: Check for complete review
-        uses: mheap/github-action-required-labels@v5
+        uses: mheap/github-action-required-labels@0ac283b4e65c1fb28ce6079dea5546ceca98ccbe # v5.5.2
         with:
           mode: exactly
           count: 1
diff --git a/.github/workflows/reusable-cifuzz.yml b/.github/workflows/reusable-cifuzz.yml
index 1986f5fb2cc640..ecb5000ee6bb8c 100644
--- a/.github/workflows/reusable-cifuzz.yml
+++ b/.github/workflows/reusable-cifuzz.yml
@@ -21,12 +21,12 @@ jobs:
     steps:
       - name: Build fuzzers (${{ inputs.sanitizer }})
         id: build
-        uses: google/oss-fuzz/infra/cifuzz/actions/build_fuzzers@master
+        uses: google/oss-fuzz/infra/cifuzz/actions/build_fuzzers@ed23f8af80ff82b25ca67cd9b101e690b8897b3f # master
         with:
           oss-fuzz-project-name: ${{ inputs.oss-fuzz-project-name }}
           sanitizer: ${{ inputs.sanitizer }}
       - name: Run fuzzers (${{ inputs.sanitizer }})
-        uses: google/oss-fuzz/infra/cifuzz/actions/run_fuzzers@master
+        uses: google/oss-fuzz/infra/cifuzz/actions/run_fuzzers@ed23f8af80ff82b25ca67cd9b101e690b8897b3f # master
         with:
           fuzz-seconds: 600
           oss-fuzz-project-name: ${{ inputs.oss-fuzz-project-name }}
@@ -34,13 +34,13 @@ jobs:
           sanitizer: ${{ inputs.sanitizer }}
       - name: Upload crash
         if: failure() && steps.build.outcome == 'success'
-        uses: actions/upload-artifact@v6
+        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
         with:
           name: ${{ inputs.sanitizer }}-artifacts
           path: ./out/artifacts
       - name: Upload SARIF
         if: always() && steps.build.outcome == 'success'
-        uses: github/codeql-action/upload-sarif@v4
+        uses: github/codeql-action/upload-sarif@c10b8064de6f491fea524254123dbe5e09572f13 # v4.35.1
         with:
           sarif_file: cifuzz-sarif/results.sarif
           checkout_path: cifuzz-sarif
diff --git a/.github/workflows/reusable-context.yml b/.github/workflows/reusable-context.yml
index fc80e6671b571c..0f0ca3475b320e 100644
--- a/.github/workflows/reusable-context.yml
+++ b/.github/workflows/reusable-context.yml
@@ -74,14 +74,14 @@ jobs:
       run-windows-tests: ${{ steps.changes.outputs.run-windows-tests }}
     steps:
     - name: Set up Python
-      uses: actions/setup-python@v6
+      uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
       with:
         python-version: "3"
 
     - run: >-
         echo '${{ github.event_name }}'
 
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       with:
         persist-credentials: false
         ref: >-
diff --git a/.github/workflows/reusable-docs.yml b/.github/workflows/reusable-docs.yml
index c1e58fd44d3790..bee44e8df27663 100644
--- a/.github/workflows/reusable-docs.yml
+++ b/.github/workflows/reusable-docs.yml
@@ -27,7 +27,7 @@ jobs:
       refspec_pr: '+${{ github.event.pull_request.head.sha }}:remotes/origin/${{ github.event.pull_request.head.ref }}'
     steps:
     - name: 'Check out latest PR branch commit'
-      uses: actions/checkout@v6
+      uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       with:
         persist-credentials: false
         ref: >-
@@ -52,7 +52,7 @@ jobs:
         git fetch origin "${refspec_base}" --shallow-since="${DATE}" \
           --no-tags --prune --no-recurse-submodules
     - name: 'Set up Python'
-      uses: actions/setup-python@v6
+      uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
       with:
         python-version: '3'
         cache: 'pip'
@@ -82,10 +82,10 @@ jobs:
     runs-on: ubuntu-24.04
     timeout-minutes: 60
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       with:
         persist-credentials: false
-    - uses: actions/cache@v5
+    - uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
       with:
         path: ~/.cache/pip
         key: ubuntu-doc-${{ hashFiles('Doc/requirements.txt') }}
@@ -108,11 +108,11 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 30
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       with:
         persist-credentials: false
     - name: 'Set up Python'
-      uses: actions/setup-python@v6
+      uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
       with:
         python-version: '3'
         cache: 'pip'
diff --git a/.github/workflows/reusable-emscripten.yml b/.github/workflows/reusable-emscripten.yml
index b79cb5bca293d6..ce3e65f11a3282 100644
--- a/.github/workflows/reusable-emscripten.yml
+++ b/.github/workflows/reusable-emscripten.yml
@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-24.04
     timeout-minutes: 40
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       with:
         persist-credentials: false
     - name: "Read Emscripten config"
@@ -38,18 +38,18 @@ jobs:
         with open(os.environ["GITHUB_ENV"], "a") as f:
             f.write(f"EMSDK_CACHE={emsdk_cache}\n")
     - name: "Install Node.js"
-      uses: actions/setup-node@v6
+      uses: actions/setup-node@53b83947a5a98c8d113130e565377fae1a50d02f # v6.3.0
       with:
         node-version: ${{ steps.emscripten-config.outputs.node-version }}
     - name: "Cache Emscripten SDK"
       id: emsdk-cache
-      uses: actions/cache@v5
+      uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
       with:
         path: ${{ env.EMSDK_CACHE }}
         key: emsdk-${{ steps.emscripten-config.outputs.emscripten-version }}-${{ steps.emscripten-config.outputs.deps-hash }}
         restore-keys: emsdk-${{ steps.emscripten-config.outputs.emscripten-version }}
     - name: "Install Python"
-      uses: actions/setup-python@v6
+      uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
       with:
         python-version: '3.x'
     - name: "Runner image version"
diff --git a/.github/workflows/reusable-macos.yml b/.github/workflows/reusable-macos.yml
index c0274c7a964781..f2e12c6c8514cd 100644
--- a/.github/workflows/reusable-macos.yml
+++ b/.github/workflows/reusable-macos.yml
@@ -28,7 +28,7 @@ jobs:
       PYTHONSTRICTEXTENSIONBUILD: 1
       TERM: linux
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       with:
         persist-credentials: false
     - name: Runner image version
diff --git a/.github/workflows/reusable-san.yml b/.github/workflows/reusable-san.yml
index b70f9b4b0d6259..ec4c51064a2c69 100644
--- a/.github/workflows/reusable-san.yml
+++ b/.github/workflows/reusable-san.yml
@@ -26,7 +26,7 @@ jobs:
     runs-on: ubuntu-24.04
     timeout-minutes: 60
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       with:
         persist-credentials: false
     - name: Runner image version
@@ -96,7 +96,7 @@ jobs:
       run: find "${GITHUB_WORKSPACE}" -name 'san_log.*' | xargs head -n 1000
     - name: Archive logs
       if: always()
-      uses: actions/upload-artifact@v6
+      uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
       with:
         name: >-
           ${{ inputs.sanitizer }}-logs-${{
diff --git a/.github/workflows/reusable-ubuntu.yml b/.github/workflows/reusable-ubuntu.yml
index 03b524e2b99250..5784da69489946 100644
--- a/.github/workflows/reusable-ubuntu.yml
+++ b/.github/workflows/reusable-ubuntu.yml
@@ -31,7 +31,7 @@ jobs:
       PYTHONSTRICTEXTENSIONBUILD: 1
       TERM: linux
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       with:
         persist-credentials: false
     - name: Register gcc problem matcher
@@ -51,7 +51,7 @@ jobs:
         echo "LD_LIBRARY_PATH=${GITHUB_WORKSPACE}/multissl/openssl/${OPENSSL_VER}/lib" >> "$GITHUB_ENV"
     - name: 'Restore OpenSSL build'
       id: cache-openssl
-      uses: actions/cache@v5
+      uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
       with:
         path: ./multissl/openssl/${{ env.OPENSSL_VER }}
         key: ${{ inputs.os }}-multissl-openssl-${{ env.OPENSSL_VER }}
diff --git a/.github/workflows/reusable-wasi.yml b/.github/workflows/reusable-wasi.yml
index 6727f00c53ccd3..c32710a411fdd4 100644
--- a/.github/workflows/reusable-wasi.yml
+++ b/.github/workflows/reusable-wasi.yml
@@ -18,17 +18,17 @@ jobs:
       CROSS_BUILD_PYTHON: cross-build/build
       CROSS_BUILD_WASI: cross-build/wasm32-wasip1
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       with:
         persist-credentials: false
     # No problem resolver registered as one doesn't currently exist for Clang.
     - name: "Install wasmtime"
-      uses: bytecodealliance/actions/wasmtime/setup@v1
+      uses: bytecodealliance/actions/wasmtime/setup@9152e710e9f7182e4c29ad218e4f335a7b203613 # v1.1.3
       with:
         version: ${{ env.WASMTIME_VERSION }}
     - name: "Restore WASI SDK"
       id: cache-wasi-sdk
-      uses: actions/cache@v5
+      uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
       with:
         path: ${{ env.WASI_SDK_PATH }}
         key: ${{ runner.os }}-wasi-sdk-${{ env.WASI_SDK_VERSION }}
@@ -39,7 +39,7 @@ jobs:
         curl -s -S --location "https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-${WASI_SDK_VERSION}/wasi-sdk-${WASI_SDK_VERSION}.0-x86_64-linux.tar.gz" | \
         tar --strip-components 1 --directory "${WASI_SDK_PATH}" --extract --gunzip
     - name: "Install Python"
-      uses: actions/setup-python@v6
+      uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
       with:
         python-version: '3.x'
     - name: "Runner image version"
diff --git a/.github/workflows/reusable-windows-msi.yml b/.github/workflows/reusable-windows-msi.yml
index c7611804369600..420c9cd909a5e9 100644
--- a/.github/workflows/reusable-windows-msi.yml
+++ b/.github/workflows/reusable-windows-msi.yml
@@ -23,7 +23,7 @@ jobs:
       ARCH: ${{ inputs.arch }}
       IncludeFreethreaded: true
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       with:
         persist-credentials: false
     - name: Build CPython installer
diff --git a/.github/workflows/reusable-windows.yml b/.github/workflows/reusable-windows.yml
index 82ea819867ef6d..7a88562239b6c5 100644
--- a/.github/workflows/reusable-windows.yml
+++ b/.github/workflows/reusable-windows.yml
@@ -26,7 +26,7 @@ jobs:
     env:
       ARCH: ${{ inputs.arch }}
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       with:
         persist-credentials: false
     - name: Register MSVC problem matcher
diff --git a/.github/workflows/stale.yml b/.github/workflows/stale.yml
index febb2dd823a8fe..845f75bafd8a41 100644
--- a/.github/workflows/stale.yml
+++ b/.github/workflows/stale.yml
@@ -14,7 +14,7 @@ jobs:
 
     steps:
     - name: "Check PRs"
-      uses: actions/stale@v9
+      uses: actions/stale@5bef64f19d7facfb25b37b414482c7164d639639 # v9.1.0
       with:
         repo-token: ${{ secrets.GITHUB_TOKEN }}
         stale-pr-message: 'This PR is stale because it has been open for 30 days with no activity.'
diff --git a/.github/workflows/tail-call.yml b/.github/workflows/tail-call.yml
index f1e342bbac28a7..a9b938fdd783cc 100644
--- a/.github/workflows/tail-call.yml
+++ b/.github/workflows/tail-call.yml
@@ -37,10 +37,10 @@ jobs:
             build_flags: ""
             run_tests: true
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: '3.11'
       - name: Build
@@ -70,10 +70,10 @@ jobs:
           - target: aarch64-apple-darwin/clang
             runner: macos-26
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: '3.11'
       - name: Install dependencies
@@ -109,10 +109,10 @@ jobs:
             runner: ubuntu-24.04-arm
             configure_flags: --with-pydebug
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: '3.11'
       - name: Build
diff --git a/.github/workflows/verify-ensurepip-wheels.yml b/.github/workflows/verify-ensurepip-wheels.yml
index 135979078710cc..cb40f6abc0b3b7 100644
--- a/.github/workflows/verify-ensurepip-wheels.yml
+++ b/.github/workflows/verify-ensurepip-wheels.yml
@@ -25,10 +25,10 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 10
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: '3'
       - name: Compare checksum of bundled wheels to the ones published on PyPI
diff --git a/.github/workflows/verify-expat.yml b/.github/workflows/verify-expat.yml
index 6b12b95cb11ff2..472a11db2da5fb 100644
--- a/.github/workflows/verify-expat.yml
+++ b/.github/workflows/verify-expat.yml
@@ -23,7 +23,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
       - name: Download and verify bundled libexpat files
diff --git a/.github/zizmor.yml b/.github/zizmor.yml
index 8b7b4de0fc8f31..7c776d5ea1f941 100644
--- a/.github/zizmor.yml
+++ b/.github/zizmor.yml
@@ -4,7 +4,3 @@ rules:
   dangerous-triggers:
     ignore:
       - documentation-links.yml
-  unpinned-uses:
-    config:
-      policies:
-        "*": ref-pin