CVE-2026-81093 — The get-html-skeleton tool fetched a URL the caller supplied after checking only its…¶

Key facts

CVE-2026-81093 is a High (8.6) vulnerability: The get-html-skeleton tool fetched a URL the caller supplied after checking only its…. This entry ships a detection-only PoC and a Docker test lab.


CVE	CVE-2026-81093
Severity	High (8.6)
Detection / prevention	—
PoC	poc.py
Source	2026/CVE-2026-81093/

Details¶

English | 한국어

Description¶

The get-html-skeleton tool fetched a URL the caller supplied after checking only its syntax. The handler in src/tools/common/get_html_skeleton.ts validated the url argument with isValidHttpUrl from src/utils/generic.ts, which confirmed the string began with an http or https scheme and parsed as a URL and inspected neither the host name nor the address it resolves to. Loopback, link-local and private ranges therefore passed, including the address cloud providers use to serve instance metadata. The unchecked URL was handed to the web-browser actor and the fetched document was returned in the tool response, so any caller of the MCP server could make it request an endpoint reachable only from the host and read the result, including instance credentials. Version 0.9.12 removes the tool.

Vulnerability Details¶

Property	Value
CVE ID	CVE-2026-81093
Type	SSRF
CVSS Score	8.6

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-81093/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-2026-81093

# 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/apify/apify-mcp-server
https://github.com/apify/apify-mcp-server/pull/572
https://github.com/apify/apify-mcp-server/security/advisories/GHSA-m28f-9v8h-gg2f
https://www.vulncheck.com/advisories/apify-actors-mcp-server-before-0.9.12-server-side-request-forgery-via-get-html-skeleton

Generated by PoC Generator on 2026-08-30T12:24:01.9707165

Frequently asked questions¶

What is CVE-2026-81093?¶

CVE-2026-81093 is a High (8.6) vulnerability: The get-html-skeleton tool fetched a URL the caller supplied after checking only its…. This entry ships a detection-only PoC and a Docker test lab.

How do I detect CVE-2026-81093?¶

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-2026-81093?¶

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.