CVE-2026-66787
Lighthouse EndpointSlice IP validation flaw enables cross-cluster DNS hijack (MITM).
Is CVE-2026-66787 being exploited?
Not confirmed. CVE-2026-66787 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.24% probability of exploitation in the next 30 days.
How severe is CVE-2026-66787?
CVE-2026-66787 is rated High with a CVSS score of 8.7. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-66787?
Yes. A fix has been recorded for CVE-2026-66787. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-66787 affect?
CVE-2026-66787 affects Red Hat Advanced Cluster Management for Kubernetes (RHACM) - lighthouse component. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-66787?
Isolate/untrust compromised spokes, restrict EndpointSlice sources, apply vendor patch when released.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Compromised spoke can inject EndpointSlice IPs so lighthouse DNS redirects service traffic to attacker endpoints, enabling MITM, data disclosure and tampering.
Immediate action required