kubernetessecurityPractitioner

Securing CI/CD for Open Source: Credentials and Verification in Kubernetes

5 min read CNCF BlogJun 26, 2026Reviewed for accuracy

Practitioner — Hands-on experience recommended

In open source projects, securing your CI/CD pipeline is critical to prevent unauthorized access and ensure the integrity of your software. With the rise of supply chain attacks, implementing robust security measures is no longer optional. This article focuses on how to manage credentials and verification processes effectively within a Kubernetes environment, emphasizing the importance of using GITHUB_TOKENs and signing container images.

The mechanism begins with the use of GITHUB_TOKENs, which by default are scoped to minimal read permissions on contents and packages. This limits exposure and reduces the risk of credential leakage. Additionally, you can manage two distinct sets of registry credentials behind separate GitHub protected environments. CI credentials can push to your development image registry, while production credentials require explicit maintainer approval before use. This layered approach ensures that sensitive operations are tightly controlled. Moreover, every actions/checkout call sets persist-credentials: false, preventing the GITHUB_TOKEN from being stored in the runner’s git config, which could lead to accidental leaks.

In production, integrating tools like Sigstore Cosign is essential. Every container image released is signed using keyless OIDC, providing an extra layer of verification. Additionally, a Software Bill of Materials (SBOM) is generated for each container image, which helps in tracking dependencies and vulnerabilities. Implementing DCO sign-off enforcement ensures that every commit carries a Signed-off-by line, further solidifying the integrity of your codebase. Be aware of the specific versions you are using; for instance, the Cosign installer is at v4.1.1 and the SBOM action at v0.24.0, which are crucial for compatibility and security enhancements.

Key takeaways

→Utilize GITHUB_TOKENs with minimal read permissions to limit exposure.
→Manage CI and production credentials in separate GitHub protected environments.
→Sign container images with Sigstore Cosign using keyless OIDC for enhanced security.
→Generate SBOMs for container images to track dependencies and vulnerabilities.
→Enforce DCO sign-off to ensure every commit is verified.

Why it matters

In production, a compromised CI/CD pipeline can lead to significant security breaches. By implementing these practices, you protect your project from potential supply chain attacks and maintain trust with your users.

Code examples

YAML

- name: Install Cosign
  uses: sigstore/cosign-installer@cad07c2e89fa2edd6e2d7bab4c1aa38e53f76003 # v4.1.1

YAML

1- name: Generate SBOM
2  uses: anchore/sbom-action@e22c389904149dbc22b58101806040fa8d37a610 # v0.24.0
3  with:
4    artifact-name: sbom_${{ inputs.sbom_name }}.spdx.json
5    output-file: ./sbom_${{ inputs.sbom_name }}.spdx.json
6    image: ${{ inputs.image_tag }}

YAML

- name: Sign Container Image
  shell: bash
  run: cosign sign -y "${{ inputs.image }}"

When NOT to use this

The official docs don't call out specific anti-patterns here. Use your judgment based on your scale and requirements.

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Securing CI/CD for Open Source: Credentials and Verification in Kubernetes

Key takeaways

Why it matters

Code examples

When NOT to use this

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