diff --git a/.github/workflows/acceptance.yml b/.github/workflows/acceptance.yml
index e369fdd..3796c0b 100644
--- a/.github/workflows/acceptance.yml
+++ b/.github/workflows/acceptance.yml
@@ -11,16 +11,19 @@ on:
     tags: ['v*.*.*']
   workflow_call:
 
+permissions:
+  contents: read
+
 jobs:
   acceptance:
     name: VM Acceptance
     runs-on: macos-15
     timeout-minutes: 30
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
 
       - name: Cache Tart images
-        uses: actions/cache@v5
+        uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5
         with:
           path: ~/.tart
           key: tart-sequoia-base-${{ hashFiles('scripts/vm-acceptance-test.sh') }}
@@ -39,7 +42,7 @@ jobs:
 
       - name: Upload logs on failure
         if: failure()
-        uses: actions/upload-artifact@v7
+        uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7
         with:
           name: acceptance-logs-${{ github.run_id }}
           path: /tmp/mac-dev-setup-*.log
diff --git a/.github/workflows/dependency-update.yml b/.github/workflows/dependency-update.yml
index 9d941ba..975c272 100644
--- a/.github/workflows/dependency-update.yml
+++ b/.github/workflows/dependency-update.yml
@@ -5,14 +5,16 @@ on:
     - cron: '0 9 * * 1'  # Monday 09:00 UTC
   workflow_dispatch:
 
+permissions:
+  contents: read
+  issues: write
+
 jobs:
   check-brewfile:
     name: Check Outdated Brewfile Packages
     runs-on: macos-latest
-    permissions:
-      issues: write
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
 
       - name: Update Homebrew
         run: brew update
diff --git a/.github/workflows/labeler.yml b/.github/workflows/labeler.yml
index 5005e35..d2541b2 100644
--- a/.github/workflows/labeler.yml
+++ b/.github/workflows/labeler.yml
@@ -13,6 +13,6 @@ jobs:
     name: Label
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/labeler@v5
+      - uses: actions/labeler@8558fd74291d67161a8a78ce36a881fa63b766a9 # v5
         with:
           repo-token: ${{ secrets.GITHUB_TOKEN }}
diff --git a/.github/workflows/release-drafter.yml b/.github/workflows/release-drafter.yml
index 3f110b5..0405e04 100644
--- a/.github/workflows/release-drafter.yml
+++ b/.github/workflows/release-drafter.yml
@@ -16,6 +16,6 @@ jobs:
     name: Update Release Draft
     runs-on: ubuntu-latest
     steps:
-      - uses: release-drafter/release-drafter@v6
+      - uses: release-drafter/release-drafter@67e173cadb2fbd3de94f4a861e0c48c913b462ae # v6
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 783c40b..ba8f9ec 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -5,6 +5,9 @@ on:
     tags:
       - 'v*.*.*'
 
+permissions:
+  contents: read
+
 jobs:
   # ── Gate: run full validation before cutting a release ────────────────────
   validate:
@@ -32,7 +35,7 @@ jobs:
     permissions:
       contents: write
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
         with:
           fetch-depth: 0
 
@@ -60,12 +63,12 @@ jobs:
           fi
 
       - name: Draft release notes
-        uses: release-drafter/release-drafter@v7
+        uses: release-drafter/release-drafter@a6acf82562eee06318b77ab8cb0b11ed81c677a7 # v7
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Create GitHub Release
-        uses: softprops/action-gh-release@v2
+        uses: softprops/action-gh-release@153bb8e04406b158c6c84fc1615b65b24149a1fe # v2
         with:
           prerelease: ${{ steps.prerelease.outputs.is_prerelease == 'true' }}
           generate_release_notes: true
diff --git a/.github/workflows/sast.yml b/.github/workflows/sast.yml
new file mode 100644
index 0000000..3b04cca
--- /dev/null
+++ b/.github/workflows/sast.yml
@@ -0,0 +1,34 @@
+name: SAST
+
+on:
+  push:
+    branches: [main, develop]
+  pull_request:
+    branches: [main, develop]
+  schedule:
+    - cron: '0 2 * * 1'  # Every Monday at 02:00 UTC
+
+permissions:
+  contents: read
+
+jobs:
+  semgrep:
+    name: Semgrep
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      security-events: write
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+
+      - uses: returntocorp/semgrep-action@713efdd345f3035192eaa63f56867b88e63e4e5d # v1
+        with:
+          config: >-
+            p/bash
+            p/secrets
+          generateSarif: "1"
+
+      - uses: github/codeql-action/upload-sarif@3b1a19a80ab047f35cbb237b5bd9bdc1e14f166c # v3
+        if: always()
+        with:
+          sarif_file: semgrep.sarif
diff --git a/.github/workflows/scorecard.yml b/.github/workflows/scorecard.yml
index e339706..9661382 100644
--- a/.github/workflows/scorecard.yml
+++ b/.github/workflows/scorecard.yml
@@ -19,22 +19,22 @@ jobs:
       contents: read
       actions: read
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
         with:
           persist-credentials: false
 
-      - uses: ossf/scorecard-action@v2.4.0
+      - uses: ossf/scorecard-action@ff5dd8929f96a8a4dc67d13f32b8c75057829621 # v2.4.0
         with:
           results_file: results.sarif
           results_format: sarif
           publish_results: true
 
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
         with:
           name: SARIF file
           path: results.sarif
           retention-days: 5
 
-      - uses: github/codeql-action/upload-sarif@v3
+      - uses: github/codeql-action/upload-sarif@3b1a19a80ab047f35cbb237b5bd9bdc1e14f166c # v3
         with:
           sarif_file: results.sarif
diff --git a/.github/workflows/stale.yml b/.github/workflows/stale.yml
index 0353e1f..426fc91 100644
--- a/.github/workflows/stale.yml
+++ b/.github/workflows/stale.yml
@@ -5,14 +5,16 @@ on:
     - cron: '0 9 * * *'
   workflow_dispatch:
 
+permissions:
+  contents: read
+  issues: write
+  pull-requests: write
+
 jobs:
   stale:
     runs-on: ubuntu-latest
-    permissions:
-      issues: write
-      pull-requests: write
     steps:
-      - uses: actions/stale@v10
+      - uses: actions/stale@b5d41d4e1d5dceea10e7104786b73624c18a190f # v10
         with:
           stale-issue-message: 'This issue has been inactive for 30 days and is marked stale. It will be closed in 7 days unless there is activity.'
           stale-pr-message: 'This PR has been inactive for 30 days and is marked stale. It will be closed in 7 days unless there is activity.'
diff --git a/.github/workflows/validate.yml b/.github/workflows/validate.yml
index bb6279b..90155ab 100644
--- a/.github/workflows/validate.yml
+++ b/.github/workflows/validate.yml
@@ -7,13 +7,16 @@ on:
     branches: [main, develop]
   workflow_call:
 
+permissions:
+  contents: read
+
 jobs:
   # ── Job 1: Lint (fast, runs on Linux) ──────────────────────────────────────
   lint:
     name: Lint
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
 
       - name: Install shellcheck
         run: sudo apt-get install -y shellcheck
@@ -50,7 +53,7 @@ jobs:
     runs-on: ubuntu-latest
     if: github.event_name == 'pull_request'
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
         with:
           fetch-depth: 0
 
@@ -129,7 +132,7 @@ jobs:
     name: Formula Audit
     runs-on: macos-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
 
       - name: Audit formula style and correctness
         run: |
@@ -145,7 +148,7 @@ jobs:
     runs-on: macos-latest
     needs: [lint, formula-audit]
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
 
       - name: Install CLI tools from Brewfile.ci
         run: |