CVE-2026-120306

Name of the Vulnerable Software and Affected Versions Beta9 build worker versions prior to 0.1.756

Description A sandbox escape exists in the image build process where shell commands in a tenant image definition are executed using Buildah with BUILDAH ISOLATION=chroot. Because the process retains the worker pod's PID, network, IPC, and user namespaces while running as uid 0 with CAP DAC OVERRIDE (a capability that allows bypassing file read, write, and execute permission checks), an attacker can access the worker container's filesystem via /proc/1/root. This allows a tenant with a workspace token to take over the build worker and read its Kubernetes service account token, as well as access the runc, buildah, and runsc binaries and host directories mounted into the pod.

Recommendations Update to version 0.1.756 or later.