CVE-2026-66039 — FFmpeg through 8.1.2, fixed in commit aafb5c6, contains a signed integer overflow…¶
Key facts
CVE-2026-66039 is a High (8.8) vulnerability: FFmpeg through 8.1.2, fixed in commit aafb5c6, contains a signed integer overflow…. This entry ships a detection-only PoC and a Docker test lab.
| CVE | CVE-2026-66039 |
| Severity | High (8.8) |
| Detection / prevention | — |
| PoC | poc.py |
| Source | 2026/CVE-2026-66039/ |
Details¶
English | 한국어
Description¶
FFmpeg through 8.1.2, fixed in commit aafb5c6, contains a signed integer overflow vulnerability in the MACE6 audio decoder that allows attackers to corrupt heap memory by supplying a crafted CAF file with a malicious bytes_per_packet value. Attackers can craft a CAF file with oversized bytes_per_packet and frames_per_packet values in the desc chunk to trigger an integer overflow in mace_decode_frame() during output sample count computation, resulting in an undersized buffer allocation and heap out-of-bounds write that could enable code execution.
Vulnerability Details¶
| Property | Value |
|---|---|
| CVE ID | CVE-2026-66039 |
| CVSS Score | 8.8 |
Proof of Concept¶
Download¶
# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-66039/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-2026-66039
# 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://code.ffmpeg.org/FFmpeg/FFmpeg/commit/aafb5c655edc76a753275c383ebb139feb032718
- https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23631
- https://www.vulncheck.com/advisories/ffmpeg-mace6-audio-decoder-heap-out-of-bounds-write-via-caf-file
Generated by PoC Generator on 2026-08-04T08:56:48.871881784
Frequently asked questions¶
What is CVE-2026-66039?¶
CVE-2026-66039 is a High (8.8) vulnerability: FFmpeg through 8.1.2, fixed in commit aafb5c6, contains a signed integer overflow…. This entry ships a detection-only PoC and a Docker test lab.
How do I detect CVE-2026-66039?¶
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-2026-66039?¶
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.