Skip to content
Fencer Vulns
high 8.7

CVE-2026-66787 json

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

published 2026-08-20 2 mo ago modified 2026-10-19 20 d ago also EUVD-2026-63533

cvss
8.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 22%
public exploits
0
none known

Summary

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.

Patch / fix

  • Red Hat Red Hat Advanced Cluster Management for Kubernetes 2.16 1790670231, 1790670243, 1790670439, 1790670912
  • Red Hat Red Hat Advanced Cluster Management for Kubernetes 2.17 1788023916, 1788023940, 1788073481, 1788105072

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-66787 updated cvss 8.7

lighthouse: lighthouse: cross-cluster DNS spoofing via unvalidated EndpointSlice IP addresses

  • Red Hat Advanced Cluster Management for Kubernetes 2.16 rhacm2/subctl-rhel9 1790670243, rhacm2/lighthouse-agent-rhel9 1790670439, rhacm2/lighthouse-coredns-rhel9 1790670231, rhacm2/submariner-rhel9-operator 1790670912
    fixed: vendor fix RHSA-2026:85227
  • Red Hat Advanced Cluster Management for Kubernetes 2.17 rhacm2/subctl-rhel9 1788105072, rhacm2/lighthouse-agent-rhel9 1788023916, rhacm2/lighthouse-coredns-rhel9 1788023940, rhacm2/submariner-rhel9-operator 1788073481
    fixed: vendor fix RHSA-2026:63016
  • Red Hat Advanced Cluster Management for Kubernetes 2.16 rhacm2/nettest-rhel9 1790702141, rhacm2/submariner-gateway-rhel9 1790670508, rhacm2/submariner-globalnet-rhel9 1790670233, rhacm2/submariner-operator-bundle 1790750775, rhacm2/submariner-route-agent-rhel9 1790670254 Red Hat Advanced Cluster Management for Kubernetes 2.17 rhacm2/nettest-rhel9 1788166791, rhacm2/submariner-gateway-rhel9 1788043964, rhacm2/submariner-globalnet-rhel9 1788043961, rhacm2/submariner-operator-bundle 1788217593, rhacm2/submariner-route-agent-rhel9 1788043970
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2 mo ago

Exploit prediction

0.30% chance of exploitation in the next 30 days, higher than 22% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.7 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N

Affected products

  • Red Hat Red Hat Advanced Cluster Management for Kubernetes 2.16
  • Red Hat Red Hat Advanced Cluster Management for Kubernetes 2.17

Classification

Weakness
  • CWE-345 Insufficient Verification of Data Authenticity

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.