RedHat AMK Lighthouse IP validation flaw enabling MITM
CVE-2026-66787 Published on August 20, 2026
Lighthouse: lighthouse: cross-cluster dns spoofing via unvalidated endpointslice ip addresses
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.
Vulnerability Analysis
CVE-2026-66787 can be exploited with network access, and requires user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality and integrity, and no impact on availability.
Timeline
Reported to Red Hat.
Made public. 24 days later.
Weakness Type
Insufficient Verification of Data Authenticity
The software does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.
Products Associated with CVE-2026-66787
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Affected Versions
Red Hat Advanced Cluster Management for Kubernetes 2.17:- Version 1788023916 and below * is unaffected.
- Version 1788023940 and below * is unaffected.
- Version 1788105072 and below * is unaffected.
- Version 1788073481 and below * is unaffected.