CVE-2026-66396 — SiYuan before v3.7.2 fails to escape the title-img Individual Attribute List value when…¶
Key facts
CVE-2026-66396 is a High (8.4) vulnerability: SiYuan before v3.7.2 fails to escape the title-img Individual Attribute List value when…. This entry ships a detection-only PoC and a Docker test lab.
| CVE | CVE-2026-66396 |
| Severity | High (8.4) |
| Detection / prevention | — |
| PoC | poc.py |
| Source | 2026/CVE-2026-66396/ |
Details¶
English | 한국어
Description¶
SiYuan before v3.7.2 fails to escape the title-img Individual Attribute List value when rendering Gallery and Kanban cover images, allowing stored cross-site scripting via unescaped style attribute interpolation. Attackers with editor permissions can inject onload handlers that execute arbitrary code in the Electron renderer with full Node.js access when victims open affected documents.
Vulnerability Details¶
| Property | Value |
|---|---|
| CVE ID | CVE-2026-66396 |
| Type | XSS |
| CVSS Score | 8.4 |
Proof of Concept¶
Download¶
# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-66396/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-2026-66396
# 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://github.com/siyuan-note/siyuan/security/advisories/GHSA-5rxg-wh59-mg34
- https://www.vulncheck.com/advisories/siyuan-before-stored-xss-to-rce-via-title-img-ial
- https://github.com/siyuan-note/siyuan/security/advisories/GHSA-5rxg-wh59-mg34
Generated by PoC Generator on 2026-08-03T19:52:42.402575126
Frequently asked questions¶
What is CVE-2026-66396?¶
CVE-2026-66396 is a High (8.4) vulnerability: SiYuan before v3.7.2 fails to escape the title-img Individual Attribute List value when…. This entry ships a detection-only PoC and a Docker test lab.
How do I detect CVE-2026-66396?¶
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-2026-66396?¶
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.