UID2-7390: add optional image_ref to shared vuln-scan notify workflow

.github/workflows/shared-vulnerability-scan-failure-notify.yaml

@@ -30,6 +30,15 @@ on:
         description: The path to the pom.xml and Dockerfile.
         type: string
         default: '.'
+      image_ref:
+        description: >-
+          An already-published image reference to scan (e.g. ghcr.io/org/app:latest). When set,
+          the JDK/Maven/Docker-build steps are skipped and this image is scanned directly — use this
+          to re-scan released images for newly-disclosed CVEs. When empty (the default), behaviour is
+          unchanged: image mode builds from source. The image must be pullable without auth (or the
+          caller must log in to the registry before invoking this workflow).
+        type: string
+        default: ''
     secrets:
       SLACK_WEBHOOK:
         required: false
@@ -50,14 +59,14 @@ jobs:
           path: uid2-shared-actions
 
       - name: Set up JDK
-        if: inputs.scan_type == 'image'
+        if: inputs.scan_type == 'image' && inputs.image_ref == ''
         uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5.2.0
         with:
           distribution: 'temurin'
           java-version: ${{ inputs.java_version }}
 
       - name: Package JAR
-        if: inputs.scan_type == 'image'
+        if: inputs.scan_type == 'image' && inputs.image_ref == ''
         id: package
         run: |
           pushd ${{ inputs.working_dir }}
@@ -71,12 +80,12 @@ jobs:
           popd
 
       - name: Extract metadata for Docker
-        if: inputs.scan_type == 'image'
+        if: inputs.scan_type == 'image' && inputs.image_ref == ''
         id: meta
         run: echo "tags=${{ steps.package.outputs.jar_version }}-${{ steps.package.outputs.git_commit }}" >> $GITHUB_OUTPUT
 
       - name: Build Docker image
-        if: inputs.scan_type == 'image'
+        if: inputs.scan_type == 'image' && inputs.image_ref == ''
         uses: docker/build-push-action@f9f3042f7e2789586610d6e8b85c8f03e5195baf # v7.2.0
         with:
           context: ${{inputs.working_dir}}
@@ -93,7 +102,8 @@ jobs:
           scan_severity: ${{ inputs.vulnerability_severity }}
           failure_severity: ${{ inputs.vulnerability_severity }}
           publish_vulnerabilities: ${{ inputs.publish_vulnerabilities }}
-          image_ref: ${{ steps.meta.outputs.tags }}
+          # Scan the explicitly-supplied published image when given; otherwise the locally-built one.
+          image_ref: ${{ inputs.image_ref != '' && inputs.image_ref || steps.meta.outputs.tags }}
           scan_type: ${{ inputs.scan_type }}
         continue-on-error: true