CVE-2026-66787
HighCVSS 8.7Exploitation Probability (EPSS)
Low risk7th percentile - higher than 7% of all known CVEs
Summary
A flaw in the lighthouse component of Red Hat Advanced Cluster Management for Kubernetes stems from insufficient validation of advertised IP addresses in EndpointSlice objects. A compromised spoke cluster can create EndpointSlices with attacker-controlled IPs, causing other clusters' lighthouse DNS to redirect legitimate service traffic to malicious endpoints, enabling Man-in-the-Middle attacks.
Risk Assessment
An attacker can intercept and modify cross-cluster traffic, leading to unauthorized information disclosure and data manipulation.
Recommendation
Upgrade Red Hat Advanced Cluster Management for Kubernetes to a patched version and restrict trust in spoke clusters.
Other vulnerabilities in Red Hat Advanced Cluster Management for Kubernetes
See all- CVE-2026-10090Critical
A flaw was found in the Application Subscription controller (multicluster-operators-subscription) of Red Hat Advanced Cluster Management for Kubernetes (ACM). A user with namespace-scoped "edit" privileges in an ACM hub namespace can create a Channel resource pointing to a Helm repository they control and a Subscription resource referencing it. The app-subscription controller fetches and applies the Helm chart contents with its own elevated authority, without verifying whether the subscription creator holds the "open-cluster-management:subscription-admin" role and without restricting applied resources to the subscription namespace. This allows the attacker to include cluster-scoped resources in the Helm chart, such as a ClusterRoleBinding granting the attacker's ServiceAccount the "cluster-admin" ClusterRole. Successful exploitation results in full cluster-admin privilege escalation.
- CVE-2026-75485Medium
In the must-gather component of Red Hat Advanced Cluster Management for Kubernetes, the cluster Proxy object is dumped in raw form, bypassing the oc inspect redaction that would normally sanitize sensitive fields. This exposes proxy basic-auth credentials in the must-gather archive, potentially disclosing sensitive authentication information to anyone with access to the archive.
- CVE-2026-73834Medium
In the must-gather component of Red Hat Advanced Cluster Management for Kubernetes, certain ACM wrapper Custom Resources that embed Secret data are collected without redaction. When an administrator runs must-gather, credentials and tokens are captured in cleartext in the resulting archive, potentially exposing sensitive information to anyone with access to the archive.
- CVE-2026-66793High
In the governance-policy-addon-controller component of Red Hat Advanced Cluster Management for Kubernetes, a user with permissions to annotate the namespaced ManagedClusterAddOn resource can override the governance-policy container image. This allows an attacker to run a controlled image with cluster-admin privileges on the managed cluster, leading to arbitrary code execution and privilege escalation.
- CVE-2026-17107High
In the service-proxy component of Red Hat Advanced Cluster Management for Kubernetes (RHACM) and multicluster-engine (MCE), the proxy appends impersonation headers without removing caller-supplied values. An authenticated hub principal can inject an Impersonate-Group header to escalate to cluster-admin on every managed cluster.
Original NVD description (English source)
A flaw was found in the lighthouse component of Red Hat Advanced Cluster Management for Kubernetes. This vulnerability stems from insufficient validation of advertised IP addresses within EndpointSlice objects. A compromised spoke cluster can exploit this by creating EndpointSlices with attacker-controlled IP addresses, causing other clusters' lighthouse DNS to redirect legitimate service traffic to malicious endpoints. This enables a remote attacker to conduct transparent Man-in-the-Middle (MITM) attacks on cross-cluster service communications, potentially leading to unauthorized information disclosure and data manipulation.