kubernetessecurityPractitioner

Securing CI/CD in Open Source: Mastering Workflow Control

5 min read CNCF BlogJun 4, 2026Reviewed for accuracy

Practitioner — Hands-on experience recommended

Securing your CI/CD pipeline is essential, especially in open source projects where contributions come from various sources. The challenge lies in preventing untrusted code from executing with elevated privileges, which can lead to significant security vulnerabilities. This is where a tool like Ariane comes into play. It acts as a gatekeeper, ensuring that only members of the organization can trigger workflows through specific commands in pull requests.

Ariane checks the commenter’s membership status within the organization and dispatches workflows accordingly. It uses the workflow_dispatch event to trigger actions. The image build workflow is designed to separate trusted and untrusted code. It first checks out the base branch to load trusted code, then performs a second checkout for the untrusted pull request branch, ensuring that no run steps execute scripts from this untrusted context. The Docker login process is secured by using environment variables like QUAY_USERNAME_CI and QUAY_PASSWORD_CI, which only allow pushes to a designated development registry.

In production, you need to configure parameters like allowed-teams to specify which teams can trigger workflows and triggers to define the commands that initiate these workflows. Be cautious, as the privileged nature of this workflow means that subsequent steps must avoid executing any untrusted code. Remember, this setup is vital for maintaining security and integrity in your CI/CD processes.

Key takeaways

→Implement Ariane to control workflow triggers based on team membership.
→Configure `allowed-teams` to restrict workflow execution to trusted members.
→Use `workflow_dispatch` to manage how workflows are triggered from pull requests.
→Separate trusted and untrusted code by checking out the base branch first.
→Secure Docker logins with environment variables to limit access.

Why it matters

In production, controlling who can trigger CI/CD workflows directly impacts your project's security posture. It reduces the risk of executing malicious code, which can compromise your entire pipeline.

Code examples

YAML

1allowed-teams:
2  - organization-members
3
4triggers:
5  /test\s*:
6    workflows:
7      - conformance-aws-cni.yaml
8      - conformance-clustermesh.yaml
9      - conformance-eks.yaml
10    # ...and so on
11    depends-on:
12      - /build-images-dependency
13  /ci-aks:
14    workflows:
15      - conformance-aks.yaml
16    depends-on:
17      - /build-images-dependency

YAML

1- name: Checkout base or default branch (trusted)
2  uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
3  with:
4    ref: ${{ github.base_ref || github.event.repository.default_branch }}
5    persist-credentials: false
6
7# ...trusted setup steps run here, including loading composite actions...
8
9# Warning: since this is a privileged workflow, subsequent workflow job
10# steps must take care not to execute untrusted code.
11- name: Checkout pull request branch (NOT TRUSTED)
12  uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
13  with:
14    persist-credentials: false
15    ref: ${{ steps.tag.outputs.sha }}