Issue Summary

atlassian/default-image:5 ships with updated components — docker-cli: 28.1.1, buildx: 0.23.0, and docker-compose: 2.36.0. These conflict with Bitbucket self-hosted runners, as the bundled Docker CLI clashes with the runner’s Docker CLI.

Steps to Reproduce

1. Run a build on a Docker Linux self-hosted runner using the build step image atlassian/default-image:5 with Docker services enabled.
2. Execute a docker build command under step script section.

Expected Results

docker build executes without errors.

Actual Results

The bundled Docker CLI routes docker build through Buildx using the docker-container driver, which tries to start a privileged moby/buildkit sidecar. This fails because --privileged=true is not allowed.

Workaround

• The issue occurs because atlassian/default-image:5 includes a Docker CLI aligned with Docker Cloud Runtime v3, which conflicts with the runner’s own CLI.

• Use atlassian/default-image:4, which does not ship with Docker CLI and respects the runner’s CLI.

• Alternatively, use a custom build step image that avoids conflicting with the runner’s Docker CLI.