CVE-2025-42599 — Active!¶

Key facts

CVE-2025-42599 is a Critical (9.8) vulnerability: Active!. This entry ships a detection-only PoC and a Docker test lab. It is on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2025-04-28), confirming active exploitation in the wild.

Actively exploited — on the CISA KEV catalog

CVE-2025-42599 is listed on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2025-04-28), confirming exploitation in the wild. Federal remediation deadline: 2025-05-19. Prioritise patching and deploy the detection and prevention rules below.


CVE	CVE-2025-42599
Severity	Critical (9.8)
CISA KEV	Actively exploited (added 2025-04-28)
Detection / prevention	—
PoC	poc.py
Source	2025/CVE-2025-42599/

Details¶

English | 한국어

Description¶

Active! mail 6 BuildInfo: 6.60.05008561 and earlier contains a stack-based buffer overflow vulnerability. Receiving a specially crafted request created and sent by a remote unauthenticated attacker may lead to arbitrary code execution and/or a denial-of-service (DoS) condition.

Vulnerability Details¶

Property	Value
CVE ID	CVE-2025-42599
CVSS Score	9.8

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2025/CVE-2025-42599/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-2025-42599

# 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://jvn.jp/en/jp/JVN22348866/
https://www.qualitia.com/jp/news/2025/04/18_1030.html
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-42599

Generated by PoC Generator on 2026-06-24T09:43:58.726288978

Frequently asked questions¶

What is CVE-2025-42599?¶

CVE-2025-42599 is a Critical (9.8) vulnerability: Active!. This entry ships a detection-only PoC and a Docker test lab. It is on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2025-04-28), confirming active exploitation in the wild.

How do I detect CVE-2025-42599?¶

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-2025-42599?¶

Upgrade to a fixed version per the vendor advisory; the NVD record lists the affected versions. Use the included PoC to verify your remediation.

Is CVE-2025-42599 actively exploited?¶

Yes. CVE-2025-42599 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, added 2025-04-28, which means it has been exploited in the wild. CISA set a federal remediation deadline of 2025-05-19. Prioritise patching and deploy the detection and prevention rules above.

For authorized security testing and research only. See the full source and NVD record.