Executive brief
Submariner is a Kubernetes operator that enables secure cross-cluster networking for services and pods across multiple clusters. A vulnerability in Submariner's Lighthouse component allows an attacker who compromises a spoke cluster to inject malicious Kubernetes resources (EndpointSlices and ServiceImports) into any namespace on peer clusters, including critical system namespaces. This could enable privilege escalation or complete cluster compromise across multiple connected infrastructure clusters.
Technical details
The vulnerability exists in Submariner's Lighthouse component where the destination namespace for resource injection is derived from attacker-controlled labels or annotations on the broker object. An attacker who gains access to a spoke cluster can manipulate these labels/annotations to specify arbitrary target namespaces on peer clusters. The flaw allows unauthorized injection of EndpointSlices and ServiceImports into any namespace, including protected system namespaces like kube-system and openshift-*. Attack preconditions include compromise of a spoke cluster connected to the Submariner federation. The vulnerability enables lateral movement and privilege escalation across the multi-cluster environment. Patches are available in Submariner v0.24 and later via Red Hat Advanced Cluster Management v2.17.
Affected products
- Red Hat Advanced Cluster Management for Kubernetes v2.17 and later contain fixes; earlier versions affected
- Submariner Lighthouse v0.24 and later contain fixes
Timeline
- 2026-08-20: disclosed
- 2026-09-03: advisory: Red Hat Security Advisory RHSA-2026:63016