CVE-2026-94485

A flaw was found in Next.js. During local development, the development server exposes a Model Context Protocol (MCP) endpoint without properly restricting cross-site requests. If a developer visits a malicious website while running the development server, an attacker can issue unauthorized requests to access sensitive project information, including file paths, source code snippets, application routes, and development logs.

This vulnerability is rated as Moderate severity because it is confined strictly to local development environments and requires user interaction, rather than directly exposing production infrastructure. Production builds do not instantiate or serve the Model Context Protocol endpoint, leaving deployed runtime workloads unaffected. Exposure is limited to scenarios where an engineer running an active local development server visits an untrusted website, which can then perform cross-origin queries to read workspace paths, logs, and route data.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.