cve-differential/README.md

CVE Differential

A self-contained Gitea and GitHub Actions composite action that extracts multi-platform SBOM attestations from container images, runs vulnerability scans with Trivy, and produces a set-based CVE delta report between a head image and a target baseline image.

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✨ Features

• Multi-Platform Support: Automatically detects and extracts SPDX SBOM attestations for multi arch images.
• Fast Attestation Extraction: Uses docker buildx imagetools inspect to extract SBOMs directly from registry manifest indices in seconds without downloading layer blobs.
• Graceful Fallbacks: If SBOM attestations or baseline images are missing, automatically falls back to generating SBOMs directly with Trivy. Using images that do contain an SBOM is highly recomended though!
• Set-Based Differential Analysis: Categorizes vulnerabilities into:
  • 🔴 Introduced Vulnerabilities (newly added in this branch / commit)
  • 🟢 Fixed Vulnerabilities (present in target baseline, resolved in this branch)
  • ⚪ Unchanged Vulnerabilities (pre-existing in target baseline)
• Secure by Default: Verified Trivy binary downloads against static SHA256 checksum lockfiles and single-step unified caching (binary + vulnerability database).

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📥 Inputs

Input	Description	Required	Default
head-image	Head container image reference to scan (e.g. registry.example.com/repo:git-sha)	Yes	—
target-image	Target baseline container image reference to compare against (e.g. registry.example.com/repo:latest)	Yes	—
target-branch	Target branch name for report headings	No	main
trivy-version	Trivy version to install and verify	No	0.74.0
output-delta	Output path for the CVE delta Markdown report	No	cve-delta.md
output-summary	Output path for the full vulnerability Markdown summary	No	cve-summary.md
write-summary	Whether to append the generated reports to the job summary ($GITHUB_STEP_SUMMARY)	No	true

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📤 Outputs

Output	Description
delta-report	Path to the generated CVE delta Markdown report
summary-report	Path to the full vulnerability Markdown summary report

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🚀 Usage Example

jobs:
  build-and-scan:
    runs-on: ubuntu-latest
    steps:
      
      - name: Build and Push Head Container Image
        uses: docker/build-push-action@v5
        with:
          context: .
          push: true
          sbom: true
          tags: registry.example.com/my-app:git-${{ github.sha }}

      - name: Compare Vulnerabilities (Head vs Target)
        uses: https://git.horstenkamp.eu/Philipp/cve-differential@main
        with:
          head-image: registry.example.com/my-app:git-${{ github.sha }}
          target-image: registry.example.com/my-app:latest
          target-branch: ${{ github.base_ref || 'main' }}

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📄 License

MIT