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CVE-2023-23456 — A heap-based buffer overflow issue was discovered in UPX in PackTmt::pack() in p_tmt.cpp…

Key facts

CVE-2023-23456 is a Medium (5.3) vulnerability: A heap-based buffer overflow issue was discovered in UPX in PackTmt::pack() in p_tmt.cpp…. This entry ships a detection-only PoC and a Docker test lab.
CVE CVE-2023-23456
Severity Medium (5.3)
Detection / prevention —
PoC poc.py
Source 2023/CVE-2023-23456/

Details

English | 한국어

Description

A heap-based buffer overflow issue was discovered in UPX in PackTmt::pack() in p_tmt.cpp file. The flow allows an attacker to cause a denial of service (abort) via a crafted file.

Vulnerability Details

Property Value
CVE ID CVE-2023-23456
Type RCE
CVSS Score 5.3

Proof of Concept

Download

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2023/CVE-2023-23456/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-2023-23456

# 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://bugzilla.redhat.com/show_bug.cgi?id=2160381
  • https://github.com/upx/upx/commit/510505a85cbe45e51fbd470f1aa8b02157c429d4
  • https://github.com/upx/upx/issues/632
  • https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EL3BVKIGG3SH6I3KPOYQAWCBD4UMPOPI/
  • https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TGEP3FBNRZXGLIA2B2ICMB32JVMPREFZ/
  • https://bugzilla.redhat.com/show_bug.cgi?id=2160381
  • https://github.com/upx/upx/commit/510505a85cbe45e51fbd470f1aa8b02157c429d4
  • https://github.com/upx/upx/issues/632
  • https://lists.debian.org/debian-lts-announce/2024/12/msg00013.html
  • https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EL3BVKIGG3SH6I3KPOYQAWCBD4UMPOPI/
  • https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TGEP3FBNRZXGLIA2B2ICMB32JVMPREFZ/

Generated by PoC Generator on 2026-01-04T14:02:24.625698993

Frequently asked questions

What is CVE-2023-23456?

CVE-2023-23456 is a Medium (5.3) vulnerability: A heap-based buffer overflow issue was discovered in UPX in PackTmt::pack() in p_tmt.cpp…. This entry ships a detection-only PoC and a Docker test lab.

How do I detect CVE-2023-23456?

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-2023-23456?

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.