CVE-2026-76412 — A vulnerability in the remote diagnostics debugger of Cisco Secure FMC Software could…¶

Key facts

CVE-2026-76412 is a High (8.5) vulnerability: A vulnerability in the remote diagnostics debugger of Cisco Secure FMC Software could…. This entry ships a detection-only PoC and a Docker test lab.


CVE	CVE-2026-76412
Severity	High (8.5)
Detection / prevention	—
PoC	poc.py
Source	2026/CVE-2026-76412/

Details¶

English | 한국어

Description¶

A vulnerability in the remote diagnostics debugger of Cisco Secure FMC Software could allow an authenticated, remote attacker to enable the remote diagnostics debugger service.

This vulnerability is due to an error when checking the privilege level of a user who is invoking remote diagnostics. An attacker could exploit this vulnerability by authenticating to the device, either through the web-based management interface or the REST API, and using the remote diagnostics debugger to grant a user elevated privileges. A successful exploit could allow the attacker to elevate privileges to root. Notes:

To exploit this vulnerability, the attacker must have valid user credentials on the affected device. The CVSSv3.1 Attack Complexity is High due to the multistage process required to fully exploit this vulnerability.

Vulnerability Details¶

Property	Value
CVE ID	CVE-2026-76412
CVSS Score	8.5

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-76412/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-2026-76412

# 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://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc2-multivulns-HXgcqRG

Generated by PoC Generator on 2026-09-17T21:32:02.216617051

Frequently asked questions¶

What is CVE-2026-76412?¶

CVE-2026-76412 is a High (8.5) vulnerability: A vulnerability in the remote diagnostics debugger of Cisco Secure FMC Software could…. This entry ships a detection-only PoC and a Docker test lab.

How do I detect CVE-2026-76412?¶

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-2026-76412?¶

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.