EUVD-2026-63533
GHSA-7fh9-j94v-w42j
Severity by source
AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N
PR:H reflects requirement for compromised spoke-cluster admin access; S:C captures DNS poisoning impact propagating to hub and peer clusters beyond the attacker's own.
Primary rating from Vendor (redhat).
CVSS VectorNVD
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N
Lifecycle Timeline
2DescriptionNVD
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.
Articles & Coverage 1
AnalysisAI
Cross-cluster MITM attacks are enabled in Red Hat Advanced Cluster Management for Kubernetes 2.x via the lighthouse service discovery component, which fails to validate IP addresses advertised in EndpointSlice objects. An attacker controlling a compromised spoke cluster can inject arbitrary IP addresses into EndpointSlices, causing lighthouse DNS resolution across all connected clusters to redirect legitimate cross-cluster service traffic to attacker-controlled endpoints. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the attacker to hold sufficient Kubernetes RBAC privileges on a spoke cluster to create or modify EndpointSlice objects - corresponding to the CVSS PR:H rating. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS base score of 8.7 reflects the Scope:Changed characteristic (S:C), which elevates severity because a single compromised spoke cluster can affect all participating clusters in the ACM fleet - not just the attacker's own environment. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Consult the Red Hat security advisory at https://access.redhat.com/security/cve/CVE-2026-66787 for the authoritative patch - no specific patched version number was present in the available data, so an exact upgrade target cannot be independently confirmed here. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all Red Hat ACM 2.x hubs and spoke clusters, then audit and restrict RBAC permissions to limit who can modify EndpointSlice objects in the lighthouse namespace. …
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