CVE-2026-75021: Fastify-CLI

High severity, CVSS 8.1. EPSS: 0.7% chance of exploitation in the next 30 days.

fastify-cli starts the Node.js Inspector when a debug flag is used, but it ignores the explicit bind address the user supplies and binds the Inspector to a broadly reachable address instead of the intended loopback. As a result the debugging interface can be exposed beyond the local machine, and because the Inspector protocol allows arbitrary code evaluation, a remote party that reaches it can achieve remote code execution on the developer's machine. This affects fastify-cli from 1.5.0 up to 8.0.1. Users should upgrade to fastify-cli 8.0.1, which honors the configured Inspector bind address.

Affected products

• Fastify-CLI Fastify-CLI: from 1.5.0, before 8.0.1 (fixed in 8.0.1)

Published 2026-09-08. Last modified 2026-09-08.