diff --git a/.github/workflows/backend-ci.yml b/.github/workflows/backend-ci.yml
index c7aa184..7c617e3 100644
--- a/.github/workflows/backend-ci.yml
+++ b/.github/workflows/backend-ci.yml
@@ -23,7 +23,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           fetch-depth: 0  # full history for branch diff logic
 
@@ -74,7 +74,7 @@ jobs:
     needs: build
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           fetch-depth: 0
       - name: Set up JDK 21
diff --git a/.github/workflows/backend-coverage.yml b/.github/workflows/backend-coverage.yml
index c32162e..484aa0a 100644
--- a/.github/workflows/backend-coverage.yml
+++ b/.github/workflows/backend-coverage.yml
@@ -16,7 +16,7 @@ jobs:
       pull-requests: write
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           fetch-depth: 0
 
diff --git a/.github/workflows/ci-guard.yml b/.github/workflows/ci-guard.yml
index e2d067d..6d71c17 100644
--- a/.github/workflows/ci-guard.yml
+++ b/.github/workflows/ci-guard.yml
@@ -9,7 +9,7 @@ jobs:
   block-backend-ci-edits:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
         with:
           fetch-depth: 0  # full history so diff-by-sha always works