CVE-2026-66794
CriticalCVSS 9.3Exploitation Probability (EPSS)
Low risk48th percentile - higher than 48% of all known CVEs
Summary
In the cluster-proxy-addon component of Multicluster Engine for Kubernetes, an unauthenticated attacker with access to the user-facing route can bypass authentication and authorization checks. By manipulating URL path segments, the attacker can proxy requests to arbitrary services across any managed cluster.
Risk Assessment
The vulnerability allows unauthorized access to internal services that should be protected, potentially leading to information disclosure or further compromise of the cluster environment.
Recommendation
Apply vendor patches and restrict access to the user-facing route to minimize the risk of exploitation.
Other vulnerabilities in Multicluster Engine for Kubernetes
See all- CVE-2026-10059Critical
A flaw was found in the Multicluster Engine for Kubernetes ClusterCurator controller. A tenant administrator with namespace-scoped privileges can exploit this vulnerability by creating a namespaced ClusterCurator. This action inadvertently grants the tenant administrator the ability to mint a token for a ServiceAccount with cluster-wide administrative authority. This leads to a privilege escalation, allowing the tenant administrator to gain full control over the cluster.
- CVE-2025-57851Medium
In Multicluster Engine for Kubernetes images, the /etc/passwd file is created with group-writable permissions. An attacker with container access, even as non-root, who is a member of the root group can modify this file and add a user with any UID, including 0, gaining full root privileges in the container.
Original NVD description (English source)
A flaw was found in the `cluster-proxy-addon` component of Multicluster Engine for Kubernetes. This vulnerability allows an unauthenticated attacker, who can access the user-facing route, to bypass authentication and authorization checks. By manipulating URL path segments, the attacker can proxy requests to arbitrary services across any managed cluster. This enables unauthorized access to internal services that would otherwise be protected, potentially leading to information disclosure or further compromise of the cluster environment.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS