CVE-2026-104846 — Seroval facilitates JS value stringification, including complex structures beyond…¶

Key facts

CVE-2026-104846 is a Critical (9.8) vulnerability: Seroval facilitates JS value stringification, including complex structures beyond…. This entry ships a detection-only PoC and a Docker test lab.


CVE	CVE-2026-104846
Severity	Critical (9.8)
Detection / prevention	—
PoC	poc.py
Source	2026/CVE-2026-104846/

Details¶

English | 한국어

Description¶

Seroval facilitates JS value stringification, including complex structures beyond JSON.stringify capabilities. From 0.12.0 until 1.6.2, fromJSON deserialization of a fulfilled Promise control node can pass a plugin-produced callable-bearing thenable to a native Promise resolver. ECMAScript thenable assimilation then invokes the callable unexpectedly, allowing attacker-controlled JSON to trigger code in applications using plugin-capable Seroval releases. This path bypasses the Promise resolver type-confusion remediation in version 1.5.3 for CVE-2026-59940 because the unexpected invocation occurs through native Promise settlement after the referenced value is deserialized. This issue is fixed in version 1.6.2.

Vulnerability Details¶

Property	Value
CVE ID	CVE-2026-104846
Type	LFI
CVSS Score	9.8

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-104846/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-2026-104846

# 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/lxsmnsyc/seroval/commit/f1ffcc96d259f9b5b3d71feb262b58240c90e7b7
https://github.com/lxsmnsyc/seroval/security/advisories/GHSA-p6vx-979v-rg4c

Generated by PoC Generator on 2026-10-03T12:37:55.048840391

Frequently asked questions¶

What is CVE-2026-104846?¶

CVE-2026-104846 is a Critical (9.8) vulnerability: Seroval facilitates JS value stringification, including complex structures beyond…. This entry ships a detection-only PoC and a Docker test lab.

How do I detect CVE-2026-104846?¶

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-2026-104846?¶

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.