CVE-2026-66785: Red Hat Advanced Cluster Management For Kubernetes 2

Low severity, CVSS 2.5. EPSS: 0.1% chance of exploitation in the next 30 days.

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.

Affected products

• Red Hat Red Hat Advanced Cluster Management For Kubernetes 2
• Red Hat Red Hat Advanced Cluster Management For Kubernetes 2.17: before 1788023916 (fixed in 1788023916); before 1788023940 (fixed in 1788023940); before 1788105072 (fixed in 1788105072); before 1788043964 (fixed in 1788043964); before 1788043961 (fixed in 1788043961); before 1788073481 (fixed in 1788073481); …

Published 2026-08-20. Last modified 2026-09-03.