CVE-2026-55518 — Avo is a framework to create admin panels for Ruby on Rails apps.¶

Key facts

CVE-2026-55518 is a Critical (9.6) vulnerability: Avo is a framework to create admin panels for Ruby on Rails apps.. This entry ships a detection-only PoC and a Docker test lab.


CVE	CVE-2026-55518
Severity	Critical (9.6)
Detection / prevention	—
PoC	poc.py
Source	2026/CVE-2026-55518/

Details¶

English | 한국어

Description¶

Avo is a framework to create admin panels for Ruby on Rails apps. Prior to 3.32.1 and 4.0.0.beta.51, Avo's association attach workflow checks attach_? in the UI and GET /resources/:resource/:id/:related/new path, but the actual write endpoint, POST /resources/:resource/:id/:related, does not run the same authorization check before mutating the association through Avo::AssociationsController#create. An authenticated low-privileged Avo user can bypass hidden or disabled attach controls and directly attach related records to a parent record by sending a crafted POST request, which can lead to privilege escalation and cross-tenant data exposure where associations represent authorization-bearing relationships. This issue is fixed in versions 3.32.1 and 4.0.0.beta.51.

Vulnerability Details¶

Property	Value
CVE ID	CVE-2026-55518
Type	RCE
CVSS Score	9.6

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-55518/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-2026-55518

# 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://github.com/avo-hq/avo/commit/995928e586fd1788dd496bd51c4dbe4a79cb2b9c
https://github.com/avo-hq/avo/pull/4568
https://github.com/avo-hq/avo/releases/tag/v3.32.1
https://github.com/avo-hq/avo/security/advisories/GHSA-8fq9-273g-6mrg

Generated by PoC Generator on 2026-07-18T09:34:34.4970228

Frequently asked questions¶

What is CVE-2026-55518?¶

CVE-2026-55518 is a Critical (9.6) vulnerability: Avo is a framework to create admin panels for Ruby on Rails apps.. This entry ships a detection-only PoC and a Docker test lab.

How do I detect CVE-2026-55518?¶

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-2026-55518?¶

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.