CVE-2023-27997 — A heap-based buffer overflow vulnerability [CWE-122] in FortiOS version 7.2.4 and below,…¶

Key facts

CVE-2023-27997 is a Critical (9.8) vulnerability: A heap-based buffer overflow vulnerability [CWE-122] in FortiOS version 7.2.4 and below,…. This entry ships a detection-only PoC and a Docker test lab. It is on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2023-06-13), confirming active exploitation in the wild, and is linked to known ransomware campaigns.

Actively exploited — on the CISA KEV catalog

CVE-2023-27997 is listed on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2023-06-13), confirming exploitation in the wild. It is linked to known ransomware campaigns. Federal remediation deadline: 2023-07-04. Prioritise patching and deploy the detection and prevention rules below.


CVE	CVE-2023-27997
Severity	Critical (9.8)
CISA KEV	Actively exploited (added 2023-06-13) · ransomware
Detection / prevention	—
PoC	poc.py
Source	2023/CVE-2023-27997/

Details¶

English | 한국어

Description¶

A heap-based buffer overflow vulnerability [CWE-122] in FortiOS version 7.2.4 and below, version 7.0.11 and below, version 6.4.12 and below, version 6.0.16 and below and FortiProxy version 7.2.3 and below, version 7.0.9 and below, version 2.0.12 and below, version 1.2 all versions, version 1.1 all versions SSL-VPN may allow a remote attacker to execute arbitrary code or commands via specifically crafted requests.

Vulnerability Details¶

Property	Value
CVE ID	CVE-2023-27997
Type	RCE
CVSS Score	9.8

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2023/CVE-2023-27997/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-2023-27997

# 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://fortiguard.com/psirt/FG-IR-23-097
https://fortiguard.com/psirt/FG-IR-23-097
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-27997

Generated by PoC Generator on 2026-06-24T23:42:35.194033695

Frequently asked questions¶

What is CVE-2023-27997?¶

CVE-2023-27997 is a Critical (9.8) vulnerability: A heap-based buffer overflow vulnerability [CWE-122] in FortiOS version 7.2.4 and below,…. This entry ships a detection-only PoC and a Docker test lab. It is on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2023-06-13), confirming active exploitation in the wild, and is linked to known ransomware campaigns.

How do I detect CVE-2023-27997?¶

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-2023-27997?¶

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-2023-27997 actively exploited?¶

Yes. CVE-2023-27997 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, added 2023-06-13, which means it has been exploited in the wild. CISA also links it to known ransomware campaigns. CISA set a federal remediation deadline of 2023-07-04. Prioritise patching and deploy the detection and prevention rules above.

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