CVE-2026-94486

A flaw was found in Next.js. The local development server exposes a Model Context Protocol (MCP) endpoint without properly restricting cross-site requests. If a developer running the development server visits a malicious website, an attacker can issue unauthorized requests to this endpoint, leading to sensitive information disclosure. This flaw allows unauthorized access to local project file locations, source code snippets from error reports, application route inventories, and development logs.

This vulnerability is rated as having Moderate impact because it exclusively targets local development environments and necessitates user interaction with an untrusted web page. Production builds and deployed production servers do not activate the Model Context Protocol endpoint, isolating exposure to active developer workstations. Furthermore, the vulnerability is limited to reading application metadata and contextual diagnostics without enabling code execution or system modification.

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.