CVE-2026-18692 — An issue in MongoDB Server's handling of timeseries bucket lifecycle could allow an…¶

Key facts

CVE-2026-18692 is a High (8.8) vulnerability: An issue in MongoDB Server's handling of timeseries bucket lifecycle could allow an…. This entry ships a detection-only PoC and a Docker test lab.


CVE	CVE-2026-18692
Severity	High (8.8)
Detection / prevention	—
PoC	poc.py
Source	2026/CVE-2026-18692/

Details¶

English | 한국어

Description¶

An issue in MongoDB Server's handling of timeseries bucket lifecycle could allow an authenticated user with write privileges to cause an internal reference to be used after the underlying memory has been freed. Subsequent operations could then result in a server crash or, potentially, execution of unintended code.

Vulnerability Details¶

Property	Value
CVE ID	CVE-2026-18692
CVSS Score	8.8

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-18692/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-2026-18692

# 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://jira.mongodb.org/browse/SERVER-129887

Generated by PoC Generator on 2026-08-13T12:25:45.009116605

Frequently asked questions¶

What is CVE-2026-18692?¶

CVE-2026-18692 is a High (8.8) vulnerability: An issue in MongoDB Server's handling of timeseries bucket lifecycle could allow an…. This entry ships a detection-only PoC and a Docker test lab.

How do I detect CVE-2026-18692?¶

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-2026-18692?¶

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.