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Most secure CI/CD and Git container images, ranked by isolation score

How isolated are the most-pulled CI/CD and Git container images when you docker run them with plain defaults, no hardening flags? This page ranks 19 build runners, CI servers, and Git forges (Jenkins, GitLab, Gitea, Drone, Concourse) on IronClaw's seven-dimension container containment scale (0-100), best-isolated first. Scores run 48/100 to 63/100 (average 54/100). Higher is safer. Every score comes from ironctl scan, a credential-free audit you can run on your own containers in ten seconds.

No CI/CD and Git image ships fully isolated by default: the leaders still leave capabilities, egress, or a writable root filesystem open. Every one of those gaps has a docker run flag that targets it, listed on every scorecard.

Ranked best to worst

Rank Image Score Grade Top gaps (default config)
🥇 1 ghcr.io/actions/actions-runner:2.321.0 63/100 🟡 C Dropped capabilities, Network isolation / egress, Read-only root filesystem
🥈 2 quay.io/argoproj/argocd:v2.13.2 63/100 🟡 C Dropped capabilities, Network isolation / egress, Read-only root filesystem
🥉 3 goharbor/harbor-core:v2.12.0 63/100 🟡 C Dropped capabilities, Network isolation / egress, Read-only root filesystem
4 jenkins/jenkins:lts 63/100 🟡 C Dropped capabilities, Network isolation / egress, Read-only root filesystem
5 sonatype/nexus3:3.75.0 63/100 🟡 C Dropped capabilities, Network isolation / egress, Read-only root filesystem
6 sonarqube:community 63/100 🟡 C Dropped capabilities, Network isolation / egress, Read-only root filesystem
7 jetbrains/teamcity-server:2024.12 63/100 🟡 C Dropped capabilities, Network isolation / egress, Read-only root filesystem
8 gitea/act_runner:0.2.11 48/100 🟠 D Dropped capabilities, Non-root user (uid != 0), Network isolation / egress
9 concourse/concourse:7.12.0 48/100 🟠 D Dropped capabilities, Non-root user (uid != 0), Network isolation / egress
10 drone/drone:2 48/100 🟠 D Dropped capabilities, Non-root user (uid != 0), Network isolation / egress
11 codeberg.org/forgejo/forgejo:9 48/100 🟠 D Dropped capabilities, Non-root user (uid != 0), Network isolation / egress
12 gitea/gitea:1.22 48/100 🟠 D Dropped capabilities, Non-root user (uid != 0), Network isolation / egress
13 gitlab/gitlab-ce:17.7.0-ce.0 48/100 🟠 D Dropped capabilities, Non-root user (uid != 0), Network isolation / egress
14 gitlab/gitlab-runner:v17.7.0 48/100 🟠 D Dropped capabilities, Non-root user (uid != 0), Network isolation / egress
15 gogs/gogs:0.13 48/100 🟠 D Dropped capabilities, Non-root user (uid != 0), Network isolation / egress
16 hashicorp/packer:1.11.2 48/100 🟠 D Dropped capabilities, Non-root user (uid != 0), Network isolation / egress
17 pulumi/pulumi:3.144.1 48/100 🟠 D Dropped capabilities, Non-root user (uid != 0), Network isolation / egress
18 rancher/rancher:v2.10.1 48/100 🟠 D Dropped capabilities, Non-root user (uid != 0), Network isolation / egress
19 hashicorp/terraform:1.10 48/100 🟠 D Dropped capabilities, Non-root user (uid != 0), Network isolation / egress

Scan your own CI/CD and Git container

These grades come from ironctl scan, one credential-free command that audits any running container, docker-compose service, or Kubernetes manifest, not just the CI/CD and Git images ranked above:

# install (Homebrew)
brew install ironsecco/ironclaw/ironclaw

# grade your own container the same way this page was generated
ironctl scan my-container

Part of the Container Isolation Scores directory. Generated from a reproducible survey by examples/isolation-survey/gen_scorecards.py and refreshed weekly, so this ranking never goes stale. Grades reflect each image's default configuration, not a limit of the image itself: the docker run flags on each page target the gaps that grade found.