diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index 990611f..13fa77d 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -7,6 +7,8 @@ updates:
       day: sunday
       time: '22:00'
       timezone: Etc/UTC
+    cooldown:
+      default-days: 7
     open-pull-requests-limit: 5
     groups:
       minor-and-patch:
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 361e4a6..918a171 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -8,14 +8,19 @@ on:
       - '**'
   pull_request:
 
+permissions:
+  contents: read
+
 jobs:
   test:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+        with:
+          persist-credentials: false
 
       - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
-        with:
+        with: # zizmor: ignore[cache-poisoning] tag builds only run the tests; nothing is published from this workflow
           node-version: 20
           cache: npm
 
diff --git a/.github/workflows/zizmor.yml b/.github/workflows/zizmor.yml
new file mode 100644
index 0000000..b9cb1a9
--- /dev/null
+++ b/.github/workflows/zizmor.yml
@@ -0,0 +1,31 @@
+name: Zizmor
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    types:
+      - opened
+      - synchronize
+      - reopened
+  schedule:
+    # Weekly: online audits (known-vulnerable actions, impostor commits) can
+    # start failing without a code change.
+    - cron: '0 4 * * 1'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+# Grouped per event, so a push to the default branch can never cancel or
+# displace the weekly run. Running pull request runs are cancelled by newer
+# ones; for other events GitHub still replaces a queued run with a newer one.
+concurrency:
+  group: zizmor-${{ github.event_name }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
+jobs:
+  zizmor:
+    name: Zizmor
+    uses: owncloud/reusable-workflows/.github/workflows/zizmor.yml@main