Packages / next / Security

LowVulnerabilityGHSA-39w2-rjm5-chcvCVE-2026-94486Published 7 Oct 2026

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

Affected releases · next

  • 16.x16.0.0 – 16.3.7Fixed in 16.3.8

On 16.x, the newest line:

npm install next@16.3.8

  1. Not affected

    0.1.0 – 15.5.28

    378 releases

  2. Affected

    16.0.0 – 16.3.7

    41 releases

  3. Fixed

    16.3.8 – 16.4.2

    4 releases, latest

423 stable releases of next, oldest to newest.

Is your project affected?

Paste your package.json, or type the range you declare for next. It is read in your browser and sent nowhere.

What happens

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.