CVE-2026-120306

Summary

A tenant with a workspace token can exploit a Buildah RUN step in a worker pod to escape isolation by leveraging shared namespaces (PID, network, IPC), CAP_DAC_OVERRIDE, and uid 0 access, allowing full read-write access to the host filesystem and sensitive binaries like runc and buildah.

Exploitability

Exploitation requires only a tenant workspace token to submit a malicious image build; no additional privileges or complex conditions are needed beyond the default Clip v2 layered builds configuration.

Blast radius

Successful exploitation grants attackers full control over the worker pod, enabling container escape, host compromise, and potential lateral movement across the cluster via stolen service account tokens and privileged binaries.

Detection

Defenders should monitor for unexpected writes to /proc/1/root or access to sensitive host paths (e.g., /usr/bin/runc, /var/run/secrets/kubernetes.io/serviceaccount) from within a Buildah container; anomalies in container filesystem activity or unusual process namespace behavior may indicate exploitation.

Prioritized remediation

Upgrade to worker version 0.1.756 or later, which enforces OCI isolation with private namespaces for Buildah RUN steps and restricts tenant ARG values to the build container only.

Analysis generated locally by garnet-coder (no data left the box). AI-assisted — verify against primary sources before acting.