diff --git a/.github/workflows/boj-build.yml b/.github/workflows/boj-build.yml
index 7c5514b..aa2e1d0 100644
--- a/.github/workflows/boj-build.yml
+++ b/.github/workflows/boj-build.yml
@@ -10,7 +10,7 @@ jobs:
     timeout-minutes: 15
     steps:
       - name: Checkout
-        uses: actions/checkout@v7.0.1
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
       - name: Trigger BoJ Server (Casket/ssg-mcp)
         run: |
           # Send a secure trigger to boj-server to build this repository
diff --git a/.github/workflows/casket-pages.yml b/.github/workflows/casket-pages.yml
index ed2db60..bfb6ac3 100644
--- a/.github/workflows/casket-pages.yml
+++ b/.github/workflows/casket-pages.yml
@@ -28,13 +28,13 @@ jobs:
     timeout-minutes: 5
     steps:
       - name: Checkout
-        uses: actions/checkout@v7.0.1
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
       - name: Setup Pages
-        uses: actions/configure-pages@v6.0.0
+        uses: actions/configure-pages@45bfe0192ca1faeb007ade9deae92b16b8254a0d  # v6.0.0
       - name: Upload artifact
-        uses: actions/upload-pages-artifact@v5.0.0
+        uses: actions/upload-pages-artifact@fc324d3547104276b827a68afc52ff2a11cc49c9  # v5.0.0
         with:
           path: 'site'
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v5.0.1
+        uses: actions/deploy-pages@368f82528645a54fb793d4d04e342629a3f51346  # v5.0.1
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 49a038a..df8a5ff 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -30,16 +30,16 @@ jobs:
             build-mode: none
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v7.0.1
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.38.0
+        uses: github/codeql-action/init@b96794f015dfd88f77b49b1c93e0fa7110f94c63  # v4.38.0
         with:
           languages: ${{ matrix.language }}
           build-mode: ${{ matrix.build-mode }}
 
       - name: Autobuild
-        uses: github/codeql-action/autobuild@v4.38.0
+        uses: github/codeql-action/autobuild@b96794f015dfd88f77b49b1c93e0fa7110f94c63  # v4.38.0
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.38.0
+        uses: github/codeql-action/analyze@b96794f015dfd88f77b49b1c93e0fa7110f94c63  # v4.38.0
diff --git a/.github/workflows/instant-sync.yml b/.github/workflows/instant-sync.yml
index 0218492..75ff2a3 100644
--- a/.github/workflows/instant-sync.yml
+++ b/.github/workflows/instant-sync.yml
@@ -18,7 +18,7 @@ jobs:
     timeout-minutes: 15
     steps:
       - name: Trigger Propagation
-        uses: peter-evans/repository-dispatch@v4.0.1
+        uses: peter-evans/repository-dispatch@28959ce8df70de7be546dd1250a005dd32156697  # v4.0.1
         with:
           token: ${{ secrets.FARM_DISPATCH_TOKEN }}
           repository: hyperpolymath/.git-private-farm
diff --git a/.github/workflows/pages.yml b/.github/workflows/pages.yml
index e56f38b..a881d1e 100644
--- a/.github/workflows/pages.yml
+++ b/.github/workflows/pages.yml
@@ -20,9 +20,9 @@ jobs:
       image: ghcr.io/stefan-hoeck/idris2-pack@sha256:f0758996a931fb35d9ecb1de273c4d59dabe2a09b433afc7e357f65a08b7e1ff
     steps:
       - name: Checkout Site
-        uses: actions/checkout@v7.0.1
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
       - name: Checkout Ddraig SSG
-        uses: actions/checkout@v7.0.1
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
         with:
           repository: hyperpolymath/ddraig-ssg
           path: .ddraig-ssg
@@ -39,7 +39,7 @@ jobs:
           fi
           ./.ddraig-ssg/build/exec/ddraig build src _site https://hyperpolymath.github.io/${GITHUB_REPOSITORY#*/}
       - name: Upload artifact
-        uses: actions/upload-pages-artifact@v5.0.0
+        uses: actions/upload-pages-artifact@fc324d3547104276b827a68afc52ff2a11cc49c9  # v5.0.0
         with:
           path: '_site'
   deploy:
@@ -52,4 +52,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v5.0.1
+        uses: actions/deploy-pages@368f82528645a54fb793d4d04e342629a3f51346  # v5.0.1
diff --git a/.github/workflows/push-email-notify.yml b/.github/workflows/push-email-notify.yml
index 8d1f093..521f1e5 100644
--- a/.github/workflows/push-email-notify.yml
+++ b/.github/workflows/push-email-notify.yml
@@ -40,7 +40,7 @@ jobs:
     timeout-minutes: 5
     steps:
       - name: Send push notification email
-        uses: hyperpolymath/smtp-notify-action@v0.3.0 # NOSONAR — pin authority is actions.lock (sha1-ede1191ef6ff3ac02c4f4d9efdf837ee517e11d7)
+        uses: hyperpolymath/smtp-notify-action@22e7bdb322c430c1d0dac6b3bb307f4bb139d0be  # NOSONAR — pin authority is actions.lock (sha1-ede1191ef6ff3ac02c4f4d9efdf837ee517e11d7)
         with:
           server_address: ${{ secrets.SMTP_HOST }}
           server_port: ${{ secrets.SMTP_PORT }}
diff --git a/.github/workflows/quality-gates.yml b/.github/workflows/quality-gates.yml
index 8e2700b..dce9de7 100644
--- a/.github/workflows/quality-gates.yml
+++ b/.github/workflows/quality-gates.yml
@@ -14,7 +14,7 @@ jobs:
     timeout-minutes: 15
     steps:
       - name: Checkout
-        uses: actions/checkout@v7.0.1
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
       - name: Install system dependencies
         run: |
           sudo apt-get update
@@ -28,13 +28,15 @@ jobs:
     timeout-minutes: 15
     steps:
       - name: Checkout
-        uses: actions/checkout@v7.0.1
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
       - name: Install Rust toolchain
         # v1 tag, not a SHA: dtolnay force-moves toolchain branches, so no
         # symbolic ref contains the old pin and lockfile generation refuses it.
         # The actions.lock records the resolved SHA; the toolchain must be an
         # explicit input because the ref no longer selects it.
-        uses: dtolnay/rust-toolchain@v1
+        uses: dtolnay/rust-toolchain@02cb101ec7c40f2c49e1d9714d64511d8e1b74de  # v1
+        with:
+          toolchain: v1
         with:
           toolchain: stable
       - name: Install system dependencies
diff --git a/.github/workflows/workflow-linter.yml b/.github/workflows/workflow-linter.yml
index 8ed9d9b..0ba8bd8 100644
--- a/.github/workflows/workflow-linter.yml
+++ b/.github/workflows/workflow-linter.yml
@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 15
     steps:
-      - uses: actions/checkout@v7.0.1
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
       - name: Check SPDX headers
         run: |
           errors=0
diff --git a/vext/.github/workflows/stress-test.yml b/vext/.github/workflows/stress-test.yml
index 90d91d1..028860f 100644
--- a/vext/.github/workflows/stress-test.yml
+++ b/vext/.github/workflows/stress-test.yml
@@ -12,7 +12,9 @@ jobs:
     steps:
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4
       - name: Install Rust toolchain
-        uses: dtolnay/rust-toolchain@stable
+        uses: dtolnay/rust-toolchain@6bed0761d98439e5a578e2877258200ad565ba87  # stable
+        with:
+          toolchain: stable
       - name: Install stress testing tools
         run: |
           sudo apt-get update