CVE-2026-79662 — Ech0 through 4.5.6 contains an OAuth redirect URI validation vulnerability in…¶

Key facts

CVE-2026-79662 is a High (8.0) vulnerability: Ech0 through 4.5.6 contains an OAuth redirect URI validation vulnerability in…. This entry ships a detection-only PoC and a Docker test lab.


CVE	CVE-2026-79662
Severity	High (8.0)
Detection / prevention	—
PoC	poc.py
Source	2026/CVE-2026-79662/

Details¶

English | 한국어

Description¶

Ech0 through 4.5.6 contains an OAuth redirect URI validation vulnerability in parseAndValidateClientRedirect (internal/service/auth/auth.go) that compares only the scheme and host of the client-supplied redirect_uri against the admin-configured allowlist, ignoring path, query, and fragment components. The redirect_uri is embedded into the signed state JWT at login time without validation. An attacker can craft a redirect_uri whose host matches an allowed origin but whose path is attacker-influenced; after the OAuth exchange the victim is redirected to that path with a one-time exchange code in the query string. If the code leaks (e.g., via Referer, analytics, or an open redirect on that host), the attacker can trade it at the public POST /api/auth/exchange endpoint for the victim's access and refresh tokens. Fixed in 4.7.3.

Vulnerability Details¶

Property	Value
CVE ID	CVE-2026-79662
CVSS Score	8.0

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-79662/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-2026-79662

# 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/lin-snow/Ech0/security/advisories/GHSA-p64j-f4x9-wq66
https://www.vulncheck.com/advisories/ech0-before-oauth-redirect-uri-validation-bypass

Generated by PoC Generator on 2026-08-25T23:20:24.625060352

Frequently asked questions¶

What is CVE-2026-79662?¶

CVE-2026-79662 is a High (8.0) vulnerability: Ech0 through 4.5.6 contains an OAuth redirect URI validation vulnerability in…. This entry ships a detection-only PoC and a Docker test lab.

How do I detect CVE-2026-79662?¶

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-2026-79662?¶

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.