diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4510385..e116fa8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -10,6 +10,8 @@ permissions: {}
 
 jobs:
   actions-lint:
+    # zizmorはセキュリティ観点のチェックのため、PR時のみ実行する
+    if: github.event_name == 'pull_request'
     runs-on: ubuntu-latest
     permissions:
       contents: read
@@ -26,6 +28,8 @@ jobs:
         uses: zizmorcore/zizmor-action@71321a20a9ded102f6e9ce5718a2fcec2c4f70d8 # v0.5.2
         with:
           min-severity: informational
+          # SARIFをCode Scanningへアップロードしない（security-events: write権限が不要になる）
+          advanced-security: false
   lint:
     runs-on: ubuntu-latest
     permissions:
@@ -35,7 +39,7 @@ jobs:
         with:
           persist-credentials: false
 
-      - uses: oven-sh/setup-bun@3d267786b128fe76c2f16a390aa2448b815359f3 # v2
+      - uses: oven-sh/setup-bun@3d267786b128fe76c2f16a390aa2448b815359f3 # v2.1.2
         with:
           bun-version: "1.3.9"
 
@@ -57,7 +61,7 @@ jobs:
         with:
           persist-credentials: false
 
-      - uses: oven-sh/setup-bun@3d267786b128fe76c2f16a390aa2448b815359f3 # v2
+      - uses: oven-sh/setup-bun@3d267786b128fe76c2f16a390aa2448b815359f3 # v2.1.2
         with:
           bun-version: "1.3.9"
 
@@ -76,7 +80,7 @@ jobs:
         with:
           persist-credentials: false
 
-      - uses: oven-sh/setup-bun@3d267786b128fe76c2f16a390aa2448b815359f3 # v2
+      - uses: oven-sh/setup-bun@3d267786b128fe76c2f16a390aa2448b815359f3 # v2.1.2
         with:
           bun-version: "1.3.9"
 
@@ -98,7 +102,7 @@ jobs:
         with:
           persist-credentials: false
 
-      - uses: oven-sh/setup-bun@3d267786b128fe76c2f16a390aa2448b815359f3 # v2
+      - uses: oven-sh/setup-bun@3d267786b128fe76c2f16a390aa2448b815359f3 # v2.1.2
         with:
           bun-version: "1.3.9"
 
@@ -117,7 +121,7 @@ jobs:
         with:
           persist-credentials: false
 
-      - uses: oven-sh/setup-bun@3d267786b128fe76c2f16a390aa2448b815359f3 # v2
+      - uses: oven-sh/setup-bun@3d267786b128fe76c2f16a390aa2448b815359f3 # v2.1.2
         with:
           bun-version: "1.3.9"
 
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 70845ca..85fcf4b 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -48,9 +48,11 @@ jobs:
         with:
           persist-credentials: false
 
-      - uses: oven-sh/setup-bun@3d267786b128fe76c2f16a390aa2448b815359f3 # v2
+      - uses: oven-sh/setup-bun@3d267786b128fe76c2f16a390aa2448b815359f3 # v2.1.2
         with:
           bun-version: "1.3.9"
+          # リリースワークフローではキャッシュ汚染を避けるためキャッシュを無効化する
+          no-cache: true
 
       - name: Install dependencies
         run: bun install --frozen-lockfile
@@ -72,9 +74,11 @@ jobs:
         with:
           persist-credentials: false
 
-      - uses: oven-sh/setup-bun@3d267786b128fe76c2f16a390aa2448b815359f3 # v2
+      - uses: oven-sh/setup-bun@3d267786b128fe76c2f16a390aa2448b815359f3 # v2.1.2
         with:
           bun-version: "1.3.9"
+          # リリースワークフローではキャッシュ汚染を避けるためキャッシュを無効化する
+          no-cache: true
 
       - name: Install dependencies
         run: bun install --frozen-lockfile
@@ -82,7 +86,8 @@ jobs:
       - name: Build
         run: bun run build
 
-      - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
+      # cacheを設定しておらず実際のキャッシュ復元は行わないため抑制する
+      - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0 # zizmor: ignore[cache-poisoning]
         with:
           node-version: '24'
           registry-url: 'https://registry.npmjs.org'