Gitea act_runner - Container Hardening Bypass via Workflow Container Options

Gitea act_runner with the Docker backend (through act 0.262.0) passes a workflow's container.options string to the Docker job container's HostConfig and, when configured with privileged: false, forces only the Privileged flag off while merging options such as --pid=host, --cap-add, and --security-opt unchanged. A user who can run a workflow on a Docker-backed runner can create a job container with host namespaces and broad capabilities and escape to the host as root despite privileged mode being disabled.