A flaw was found in Submariner. This vulnerability allows a malicious cluster (spoke) to redirect network traffic from other connected clusters (peer clusters) by publishing a specially crafted network endpoint. The system fails to properly validate the network subnets provided by the malicious cluster, enabling it to declare arbitrary network ranges. Consequently, all network traffic intended for these arbitrary ranges from peer clusters will be rerouted through the attacker's tunnel, potentially leading to unauthorized information disclosure or network disruption.

A critical flaw was discovered in Submariner, a tool used to connect Kubernetes clusters across different environments. The vulnerability allows a malicious cluster (spoke) to redirect network traffic from peer clusters by publishing a specially crafted network endpoint. The root cause is insufficient validation of network subnets provided by connecting clusters, allowing attackers to declare arbitrary network ranges. Once exploited, all traffic destined for those arbitrary ranges from peer clusters gets rerouted through the attacker's tunnel. This can lead to unauthorized information disclosure and network disruption across multi-cluster environments. The vulnerability is particularly dangerous in multi-cloud or hybrid cloud deployments that rely on Submariner for cross-cluster connectivity. Red Hat has acknowledged the issue and it is tracked under Bugzilla ID 2507530.