CVE-2026-66788: Access Control Flaw (CVSS 9.9)

Description

A flaw was found in Lighthouse. A remote attacker, by compromising a spoke cluster, can exploit a vulnerability where the destination namespace for resource injection is derived from an attacker-controlled label or annotation on the broker object. This allows the attacker to inject unauthorized EndpointSlices and ServiceImports into any namespace on peer clusters, including critical system namespaces like kube-system and openshift-*. This could lead to privilege escalation or other forms of system compromise within the cluster.

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CVSS v3.1 Score

9.9

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0028

Probability of exploitation

0.21%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-284 CWE-284

References

Other References

https://access.redhat.com/security/cve/CVE-2026-66788 https://bugzilla.redhat.com/show_bug.cgi?id=2507533

Frequently Asked Questions

What is CVE-2026-66788? +

A flaw was found in Lighthouse. A remote attacker, by compromising a spoke cluster, can exploit a vulnerability where the destination namespace for resource injection is derived from an attacker-controlled label or annotation on the broker object. This allows the attacker to inject unauthorized EndpointSlices and ServiceImports into any namespace on peer clusters, including critical system namespaces like kube-system and openshift-*. This could lead to privilege escalation or other forms of system compromise within the cluster. It has a CVSS v3.1 base score of 9.9 (CRITICAL).

How severe is CVE-2026-66788? +

CVE-2026-66788 has a CVSS v3.1 score of 9.9 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0028, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-66788? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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