diff --git a/.github/workflows/heavy.yml b/.github/workflows/heavy.yml
index 136132f96..af74efedb 100644
--- a/.github/workflows/heavy.yml
+++ b/.github/workflows/heavy.yml
@@ -6,21 +6,26 @@ on: # rebuild any PRs and main branch changes
     branches:
       - master
 
+permissions:
+  contents: read
+
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
   cancel-in-progress: true
 
 jobs:
   build-and-test:
+    permissions:
+      contents: read
     timeout-minutes: 20
     runs-on: ubuntu-latest-16-cores
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
         with:
           submodules: recursive
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable
       - name: Install protoc
-        uses: arduino/setup-protoc@v3
+        uses: arduino/setup-protoc@c65c819552d16ad3c9b72d9dfd5ba5237b9c906b # v3
         with:
           # TODO: Upgrade proto once https://github.com/arduino/setup-protoc/issues/99 is fixed
           version: "23.x"
diff --git a/.github/workflows/per-pr.yml b/.github/workflows/per-pr.yml
index ae9ab7455..c8ad3e836 100644
--- a/.github/workflows/per-pr.yml
+++ b/.github/workflows/per-pr.yml
@@ -20,18 +20,18 @@ jobs:
     timeout-minutes: ${{ github.ref == 'refs/heads/master' && 15 || 10 }}
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
         with:
           submodules: recursive
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable
       - name: Install protoc
-        uses: arduino/setup-protoc@v3
+        uses: arduino/setup-protoc@c65c819552d16ad3c9b72d9dfd5ba5237b9c906b # v3
         with:
           # TODO: Upgrade proto once https://github.com/arduino/setup-protoc/issues/99 is fixed
           version: "23.x"
           repo-token: ${{ secrets.GITHUB_TOKEN }}
       - run: rustup component add rustfmt clippy
-      - uses: Swatinem/rust-cache@v2
+      - uses: Swatinem/rust-cache@e18b497796c12c097a38f9edb9d0641fb99eee32 # v2
         with:
           save-if: ${{ github.ref == 'refs/heads/master' }}
       - run: cargo fmt --all --check
@@ -63,10 +63,10 @@ jobs:
             timeoutMinutes: 20
     runs-on: ${{ matrix.runsOn || matrix.os }}
     steps:
-      - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+      - uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable
       - name: Install protoc
-        uses: arduino/setup-protoc@v3
+        uses: arduino/setup-protoc@c65c819552d16ad3c9b72d9dfd5ba5237b9c906b # v3
         with:
           # TODO: Upgrade proto once https://github.com/arduino/setup-protoc/issues/99 is fixed
           version: "23.x"
@@ -76,11 +76,11 @@ jobs:
       # Visual Studio bug tracker https://developercommunity.visualstudio.com/t/Regression-from-1943:-linkexe-crashes/10912960
       - name: Setup RUSTFLAGS (Windows)
         if: runner.os == 'Windows'
-        uses: actions/github-script@v7
+        uses: actions/github-script@450193c5abd4cdb17ba9f3ffcfe8f635c4bb6c2a # v9
         with:
           script: |
             core.exportVariable('RUSTFLAGS', '-Csymbol-mangling-version=v0');
-      - uses: Swatinem/rust-cache@v2
+      - uses: Swatinem/rust-cache@e18b497796c12c097a38f9edb9d0641fb99eee32 # v2
         with:
           save-if: ${{ github.ref == 'refs/heads/master' }}
       - run: cargo test -- --include-ignored --nocapture
@@ -91,16 +91,16 @@ jobs:
           test_executable=$(cargo build --tests --message-format json | jq -r 'select(.profile?.test == true and .target?.name == "temporalio_sdk_core" and .executable) | .executable')
           cp $test_executable ./core-tests
       - name: Upload cgroup test executable
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7
         if: runner.os == 'Linux' && runner.arch == 'X64'
         with:
           name: cgroup-tests-linux-x86_64
           path: ./core-tests
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7
         with:
           name: coverage-report
           path: tarpaulin-report.html
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7
         with:
           name: state-machine-coverage
           path: machine_coverage/
@@ -110,18 +110,18 @@ jobs:
     timeout-minutes: ${{ github.ref == 'refs/heads/master' && 15 || 10 }}
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
         with:
           submodules: recursive
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable
       - name: Install protoc
-        uses: arduino/setup-protoc@v3
+        uses: arduino/setup-protoc@c65c819552d16ad3c9b72d9dfd5ba5237b9c906b # v3
         with:
           # TODO: Upgrade proto once https://github.com/arduino/setup-protoc/issues/99 is fixed
           version: "23.x"
           repo-token: ${{ secrets.GITHUB_TOKEN }}
       - run: rustup component add rustfmt clippy
-      - uses: Swatinem/rust-cache@v2
+      - uses: Swatinem/rust-cache@e18b497796c12c097a38f9edb9d0641fb99eee32 # v2
         with:
           save-if: ${{ github.ref == 'refs/heads/master' }}
           key: msrv
@@ -140,7 +140,7 @@ jobs:
       CGROUP_TESTS_ENABLED: true
     steps:
       - name: Download cgroup test executable
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8
         with:
           name: cgroup-tests-linux-x86_64
       - name: Run tests
@@ -166,10 +166,10 @@ jobs:
             runsOn: macos-15-intel
     runs-on: ${{ matrix.runsOn || matrix.os }}
     steps:
-      - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+      - uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable
       - name: Install protoc
-        uses: arduino/setup-protoc@v3
+        uses: arduino/setup-protoc@c65c819552d16ad3c9b72d9dfd5ba5237b9c906b # v3
         with:
           # TODO: Upgrade proto once https://github.com/arduino/setup-protoc/issues/99 is fixed
           version: "23.x"
@@ -179,11 +179,11 @@ jobs:
       # Visual Studio bug tracker https://developercommunity.visualstudio.com/t/Regression-from-1943:-linkexe-crashes/10912960
       - name: Setup RUSTFLAGS (Windows)
         if: runner.os == 'Windows'
-        uses: actions/github-script@v7
+        uses: actions/github-script@450193c5abd4cdb17ba9f3ffcfe8f635c4bb6c2a # v9
         with:
           script: |
             core.exportVariable('RUSTFLAGS', '-Csymbol-mangling-version=v0');
-      - uses: Swatinem/rust-cache@v2
+      - uses: Swatinem/rust-cache@e18b497796c12c097a38f9edb9d0641fb99eee32 # v2
         with:
           save-if: ${{ github.ref == 'refs/heads/master' }}
       - run: cargo integ-test
@@ -199,16 +199,16 @@ jobs:
     timeout-minutes: ${{ github.ref == 'refs/heads/master' && 25 || 20 }}
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+      - uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable
       - name: Install protoc
-        uses: arduino/setup-protoc@v3
+        uses: arduino/setup-protoc@c65c819552d16ad3c9b72d9dfd5ba5237b9c906b # v3
         with:
           # TODO: Upgrade proto once https://github.com/arduino/setup-protoc/issues/99 is fixed
           version: "23.x"
           repo-token: ${{ secrets.GITHUB_TOKEN }}
 
-      - uses: Swatinem/rust-cache@v2
+      - uses: Swatinem/rust-cache@e18b497796c12c097a38f9edb9d0641fb99eee32 # v2
         with:
           save-if: ${{ github.ref == 'refs/heads/master' }}
       - run: cargo test --features=test-utilities --test cloud_tests
@@ -224,19 +224,19 @@ jobs:
     timeout-minutes: ${{ github.ref == 'refs/heads/master' && 25 || 20 }}
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+      - uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable
       - name: Install protoc
-        uses: arduino/setup-protoc@v3
+        uses: arduino/setup-protoc@c65c819552d16ad3c9b72d9dfd5ba5237b9c906b # v3
         with:
           # TODO: Upgrade proto once https://github.com/arduino/setup-protoc/issues/99 is fixed
           version: "23.x"
           repo-token: ${{ secrets.GITHUB_TOKEN }}
       - name: Start container for otel-collector and prometheus
-        uses: hoverkraft-tech/compose-action@v2.0.1
+        uses: hoverkraft-tech/compose-action@4894d2492015c1774ee5a13a95b1072093087ec3 # v2.5.0
         with:
           compose-file: ./etc/docker/docker-compose-ci.yaml
-      - uses: Swatinem/rust-cache@v2
+      - uses: Swatinem/rust-cache@e18b497796c12c097a38f9edb9d0641fb99eee32 # v2
         with:
           save-if: ${{ github.ref == 'refs/heads/master' }}
       - run: cargo integ-test docker_
@@ -246,20 +246,20 @@ jobs:
     timeout-minutes: 15
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+      - uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable
       - name: Install protoc
-        uses: arduino/setup-protoc@v3
+        uses: arduino/setup-protoc@c65c819552d16ad3c9b72d9dfd5ba5237b9c906b # v3
         with:
           version: "23.x"
           repo-token: ${{ secrets.GITHUB_TOKEN }}
-      - uses: Swatinem/rust-cache@v2
+      - uses: Swatinem/rust-cache@e18b497796c12c097a38f9edb9d0641fb99eee32 # v2
         with:
           save-if: ${{ github.ref == 'refs/heads/master' }}
       - name: Build examples
         run: cargo build --examples -p temporalio-sdk --features examples
       - name: Install Temporal CLI
-        uses: temporalio/setup-temporal@v0
+        uses: temporalio/setup-temporal@1059a504f87e7fa2f385e3fa40d1aa7e62f1c6ca # v0
       - name: Start Temporal dev server
         run: |
           temporal server start-dev --headless &
@@ -281,10 +281,10 @@ jobs:
     name: "C bridge static link test"
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+      - uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # stable
       - name: Install protoc
-        uses: arduino/setup-protoc@v3
+        uses: arduino/setup-protoc@c65c819552d16ad3c9b72d9dfd5ba5237b9c906b # v3
         with:
           # TODO: Upgrade proto once https://github.com/arduino/setup-protoc/issues/99 is fixed
           version: "23.x"