diff --git a/.gitea/workflows/build.yml b/.gitea/workflows/build.yml
index c88b7ff..ba28bab 100644
--- a/.gitea/workflows/build.yml
+++ b/.gitea/workflows/build.yml
@@ -108,6 +108,11 @@ jobs:
         if: github.event_name != 'pull_request' && env.IS_TEST_BUILD == 'false'
         uses: sigstore/cosign-installer@v4.1.2
 
+      - name: Install Skopeo
+        if: github.event_name != 'pull_request' && env.IS_TEST_BUILD == 'false'
+        run: |
+          sudo apt-get update && sudo apt-get install -y skopeo
+
       - name: Sign container image (True Outer Digest)
         if: github.event_name != 'pull_request' && env.IS_TEST_BUILD == 'false'
         env:
@@ -117,9 +122,9 @@ jobs:
           # 1. Cosign an der Gitea-Registry anmelden
           echo "${{ secrets.REGISTRY }}" | cosign login "${{ env.REGISTRY_HOST }}" -u "${{ github.repository_owner }}" --password-stdin
           
-          # 2. Mit skopeo den echten, äußeren Manifest-List-Digest von Gitea abfragen
-          echo "Frage finalen Manifest-List-Digest von Gitea ab..."
-          OUTER_DIGEST=$(skopeo inspect --creds "${{ github.repository_owner }}:${{ secrets.REGISTRY }}" docker://${{ env.IMAGE_REGISTRY }}/${{ env.IMAGE_NAME }}:stable | jq -r .Digest)
+          # 2. Skopeo als Docker-Container ausführen, um den Digest zu holen
+          echo "Frage finalen Manifest-List-Digest via Skopeo-Container ab..."
+          OUTER_DIGEST=$(docker run --rm quay.io/skopeo/stable inspect --creds "${{ github.repository_owner }}:${{ secrets.REGISTRY }}" docker://${{ env.IMAGE_REGISTRY }}/${{ env.IMAGE_NAME }}:stable | jq -r .Digest)
           
           # 3. Die Referenz exklusiv über den äußeren Digest bauen
           IMAGE_REF="${{ env.IMAGE_REGISTRY }}/${{ env.IMAGE_NAME }}@${OUTER_DIGEST}"