A privilege escalation vulnerability affects Woodpecker instances using the Kubernetes backend.
The pipeline option backend_options.kubernetes.serviceAccountName was passed directly to the pod spec without any admin gating.
Who is impacted: any operator running the Kubernetes backend. Any user with Push permission on a connected repository can run pipeline pods under an arbitrary ServiceAccount in the pipeline namespace, gaining that account's RBAC permissions. If a privileged ServiceAccount is reachable in that namespace, this can lead to secret exfiltration (database credentials, API keys, TLS certs) and full cluster takeover.
Operators who cannot upgrade immediately can mitigate by any of:
Restrict Push access on repositories connected to the Kubernetes-backed instance to
trusted users only.
Harden the pipeline namespace: ensure no privileged ServiceAccount exists or is bound in
the namespace where pipeline pods run; keep the default ServiceAccount minimally privileged.
Disable ServiceAccount token automounting for ServiceAccounts that should not be used by
pipelines.
Enforce an admission policy (e.g. OPA/Gatekeeper, Kyverno, or a ValidatingAdmissionPolicy)
that rejects pipeline pods setting an unexpected serviceAccountName.
Use a dedicated, isolated namespace per org/instance with no sensitive RBAC bindings.
Resources
Vulnerable option introduced in commit 609ba481b5e912f59aaae8ca7bc22b44523c5e37
Affected versions: v1.0.0 through v3.15.0
Source: pipeline/backend/kubernetes/backend_options.go (field ServiceAccountName),
pipeline/backend/kubernetes/pod.go (assigned to pod spec with no gating)