Next.js has information disclosure in development server's Model Context Protocol endpoint

MEDIUM 5.4CVE-2026-94486 · GHSA-39w2-rjm5-chcv · Published 02/10/2026 · updated 05/10/2026

Package	Affected versions	Patched versions
next.js vercel	`≥ 16.0.0, < 16.3.8`	`16.3.8`
next npm	`≥ 16.0.0, < 16.3.8`	`16.3.8`

Description

The Next.js development server (next dev) exposes a Model Context Protocol endpoint that does not verify which website a request originates from, allowing a malicious website visited by the developer to read sensitive development data — including the project's location on disk, source code snippets from error reports, the route inventory, and development logs. Only applications run with next dev are affected. Production deployments do not serve this endpoint.

NVD 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.

References

vercel/next.js security advisory · WEB
nvd.nist.gov/vuln/detail/CVE-2026-94486 · ADVISORY
vercel/next.js commit 2d9f50a · WEB
vercel/next.js · PACKAGE
vercel/next.js release v16.3.8 · WEB

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Package

Affected versions

Patched versions

next.js

vercel

≥ 16.0.0, < 16.3.8

16.3.8

npm

≥ 16.0.0, < 16.3.8

16.3.8

Description

NVD description