diff --git a/.github/workflows/check-commits.yml b/.github/workflows/check-commits.yml
index c4d15bacf70a6..5423e0580c921 100644
--- a/.github/workflows/check-commits.yml
+++ b/.github/workflows/check-commits.yml
@@ -13,6 +13,13 @@ jobs:
       matrix:
         check: [commit-msg, pr_check]
     steps:
+    - name: set CI_BASE_BRANCH
+      run: |
+          if [ -n "${{ github.base_ref }}" ]; then
+              echo "CI_BASE_BRANCH=${{ github.base_ref }}" >> $GITHUB_ENV
+          elif [ -n "${{ github.event.merge_group.base_ref }}" ]; then
+              echo "CI_BASE_BRANCH=${{ github.event.merge_group.base_ref }}" | sed s.=refs/heads/.=. >> $GITHUB_ENV
+          fi
     - uses: actions/checkout@main
       with:
         # Use the SHA of the PR branch as-is, not the PR branch merged
@@ -22,10 +29,10 @@ jobs:
         fetch-depth: 0
     - name: Fetch base branch
       run:
-        git fetch origin '${{ github.base_ref }}:${{ github.base_ref }}'
+        git fetch origin "${CI_BASE_BRANCH}:${CI_BASE_BRANCH}"
     - name: Run checks
       run: |
-        ./dist/tools/${{ matrix.check }}/check.sh "${{ github.base_ref }}"
+        ./dist/tools/${{ matrix.check }}/check.sh "${CI_BASE_BRANCH}"
   check-commits-success:
     needs: check-commits
     if: github.event_name != 'merge_group'