diff --git a/.github/workflows/cd-production.yml b/.github/workflows/cd-production.yml
index 0b190e0..5e6edda 100644
--- a/.github/workflows/cd-production.yml
+++ b/.github/workflows/cd-production.yml
@@ -64,7 +64,7 @@ jobs:
 
     steps:
       - name: 📥 Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           ref: ${{ github.event.workflow_run.head_sha }}
 
@@ -124,7 +124,7 @@ jobs:
 
     steps:
       - name: 📥 Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           ref: ${{ github.event.workflow_run.head_sha }}
 
@@ -239,7 +239,7 @@ jobs:
 
     steps:
       - name: 📥 Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           ref: ${{ github.event.workflow_run.head_sha }}
           fetch-depth: 0
diff --git a/.github/workflows/cd-staging.yml b/.github/workflows/cd-staging.yml
index 34de014..acb5c38 100644
--- a/.github/workflows/cd-staging.yml
+++ b/.github/workflows/cd-staging.yml
@@ -56,7 +56,7 @@ jobs:
 
     steps:
       - name: 📥 Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           ref: ${{ github.event.workflow_run.head_sha }}
 
@@ -100,7 +100,7 @@ jobs:
       url: ${{ steps.deploy.outputs.url }}
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           ref: ${{ github.event.workflow_run.head_sha }}
 
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index aa6ff60..408db11 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -41,7 +41,7 @@ jobs:
 
     steps:
       - name: 📥 Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: ⚙️ Set up Node.js ${{ env.NODE_VERSION }}
         uses: actions/setup-node@v4
@@ -70,7 +70,7 @@ jobs:
         working-directory: ./backend
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - uses: actions/setup-node@v4
         with:
@@ -123,7 +123,7 @@ jobs:
         working-directory: ./backend
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: actions/setup-node@v4
         with:
           node-version: ${{ env.NODE_VERSION }}
@@ -158,7 +158,7 @@ jobs:
 
     steps:
       - name: 📥 Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: ⚙️ Set up Node.js ${{ env.NODE_VERSION }}
         uses: actions/setup-node@v4
@@ -208,7 +208,7 @@ jobs:
         working-directory: ./frontend
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: actions/setup-node@v4
         with:
           node-version: ${{ env.NODE_VERSION }}
@@ -240,7 +240,7 @@ jobs:
         working-directory: ./frontend
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: actions/setup-node@v4
         with:
           node-version: ${{ env.NODE_VERSION }}
diff --git a/.github/workflows/security-audit.yml b/.github/workflows/security-audit.yml
index 65a255a..d504e42 100644
--- a/.github/workflows/security-audit.yml
+++ b/.github/workflows/security-audit.yml
@@ -40,7 +40,7 @@ jobs:
         working-directory: ./backend
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - uses: actions/setup-node@v4
         with:
@@ -104,7 +104,7 @@ jobs:
         working-directory: ./frontend
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - uses: actions/setup-node@v4
         with:
@@ -161,7 +161,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0    # Full history for commit-level scanning
 
@@ -216,7 +216,7 @@ jobs:
     if: github.event_name == 'schedule' || github.event_name == 'workflow_dispatch'
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - uses: actions/setup-node@v4
         with: