Vulnerability · Published Aug 20, 2026 · Assigned by redhat

CVE-2026-66787Lighthouse: lighthouse: cross-cluster dns spoofing via unvalidated endpointslice ip addresses

High 8.7

In plain English

A high-severity insufficient verification of data authenticity in Red Hat Advanced Cluster Management for Kubernetes 2.16 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 23% of all known vulnerabilities).

Severity (CVSS 3.1)8.7High

Exploit odds (30 days)0.3%top 77.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
Red Hat	Red Hat Advanced Cluster Management for Kubernetes 2.16	see references
Red Hat	Red Hat Advanced Cluster Management for Kubernetes 2.16	see references
Red Hat	Red Hat Advanced Cluster Management for Kubernetes 2.16	see references
Red Hat	Red Hat Advanced Cluster Management for Kubernetes 2.16	see references
Red Hat	Red Hat Advanced Cluster Management for Kubernetes 2.17	see references
Red Hat	Red Hat Advanced Cluster Management for Kubernetes 2.17	see references
Red Hat	Red Hat Advanced Cluster Management for Kubernetes 2.17	see references
Red Hat	Red Hat Advanced Cluster Management for Kubernetes 2.17	see references

Weakness: CWE-345 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N

References

RHSA-2026:63016 vendor-advisory, x_refsource_REDHAT
RHSA-2026:85227 vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-66787 vdb-entry, x_refsource_REDHAT
RHBZ#2507532 issue-tracking, x_refsource_REDHAT