CVE-2026-94486
Received Received - Intake

Next.js Dev Server MCP Endpoint Exposure Leads to Information Disclosure

Publication date: 2026-10-02

Last updated on: 2026-10-02

Assigner: GitHub, Inc.

Description
Next.js is a React framework for building full-stack web applications. From 16.0.0 until 16.3.8, the next dev development server exposes a Model Context Protocol endpoint without reliably restricting cross-site requests. A malicious website visited by a developer can reach the endpoint and read the project's disk location, source code snippets from error reports, route inventory, and development logs. Production deployments do not serve this endpoint. This issue is fixed in version 16.3.8.

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Meta Information

Published
2026-10-02
Last Modified
2026-10-02
Generated
2026-10-02
AI Q&A
2026-10-02
EPSS Evaluated
N/A
NVD
CVE-2026-94486
EUVD
EUVD-2026-91667

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
vercel next.js to 16.3.8 (inc)
vercel next.js From 16.0.0 (inc) to 16.3.8 (inc)
vercel next.js 16.3.8

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-346 The product does not properly verify that the source of data or communication is valid.

Attack-Flow Graph

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Executive Summary

This vulnerability is an information disclosure issue in Next.js's development server (next dev) versions 16.0.0 to 16.3.7. It involves a Model Context Protocol endpoint that does not restrict cross-site requests, allowing a malicious website visited by a developer to access sensitive project data such as disk location, source code snippets, route inventory, and development logs.

Detection Guidance

Check if the Next.js development server (next dev) is running on your system. Look for exposed Model Context Protocol endpoints on ports typically used by development servers (e.g., 3000, 8000). Use network scanning tools like nmap to identify open ports and services.

Impact Analysis

If exploited, this vulnerability could allow an attacker to read your project's sensitive information, including source code and development logs, potentially exposing intellectual property or confidential data. However, it requires the attacker to trick a developer into visiting a malicious site while the Next.js dev server is running.

Mitigation Strategies

Upgrade Next.js to version 16.3.8 or later to patch the vulnerability. Avoid running the development server in production environments. If immediate upgrade is not possible, restrict access to the development server by binding it to localhost only.

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