CVE-2026-66787 — A flaw was found in the lighthouse component of Red Hat Advanced Cluster Management for…¶

Key facts

CVE-2026-66787 is a High (8.7) vulnerability: A flaw was found in the lighthouse component of Red Hat Advanced Cluster Management for…. This entry ships a detection-only PoC and a Docker test lab.


CVE	CVE-2026-66787
Severity	High (8.7)
Detection / prevention	—
PoC	poc.py
Source	2026/CVE-2026-66787/

Details¶

English | 한국어

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.

Vulnerability Details¶

Property	Value
CVE ID	CVE-2026-66787
CVSS Score	8.7

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-66787/poc.py

Usage¶

# Run PoC against target
python3 poc.py --target <TARGET_URL>

# With authentication
python3 poc.py --target <TARGET_URL> --username <USER> --password <PASS>

⚠️ Warning: This PoC is for authorized security testing only. It uses detection-only techniques and does not exploit or damage target systems.

Test Lab¶

This repository includes a Docker-based test environment with both vulnerable and patched applications.

Quick Start¶

# Clone and navigate to CVE directory
cd CVE-2026-66787

# Start both applications
docker-compose up -d

# Run tests
./run-tests.sh    # Linux/Mac
./run-tests.ps1   # Windows PowerShell

Application Endpoints¶

Application	URL	Status
Vulnerable App	http://localhost:8080	Shows vulnerability
Patched App	http://localhost:8081	Demonstrates fix

Directory Structure¶

├── README.md           # English documentation
├── README_KO.md        # Korean documentation
├── poc.py              # PoC detection script
├── docker-compose.yml  # Container orchestration
├── run-tests.sh        # Linux/Mac test runner
├── run-tests.ps1       # Windows test runner
├── vulnerable-app/     # Vulnerable version
│   ├── app.py
│   ├── Dockerfile
│   └── requirements.txt
└── patched-app/        # Fixed version
    ├── app.py
    ├── Dockerfile
    └── requirements.txt

References¶

https://access.redhat.com/security/cve/CVE-2026-66787
https://bugzilla.redhat.com/show_bug.cgi?id=2507532

Generated by PoC Generator on 2026-08-22T23:52:43.541931797

Frequently asked questions¶

What is CVE-2026-66787?¶

CVE-2026-66787 is a High (8.7) vulnerability: A flaw was found in the lighthouse component of Red Hat Advanced Cluster Management for…. This entry ships a detection-only PoC and a Docker test lab.

How do I detect CVE-2026-66787?¶

Run the detection-only PoC included with this entry against your Docker test lab to confirm whether a target is affected; pair it with your own IDS logging.

How do I block or mitigate CVE-2026-66787?¶

Upgrade to a fixed version per the vendor advisory; the NVD record lists the affected versions. Use the included PoC to verify your remediation.

For authorized security testing and research only. See the full source and NVD record.