Vulnerability in Fastify-Cli

CVE-2026-75021

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.007 (52.8th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 52.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-75021: held from 0.007 to 0.007.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-75021?
CVE-2026-75021 is a high-severity vulnerability in Fastify-Cli, classified under CWE-1327. CVSS score: 8.1/10. Published 2026-09-08.
How severe is CVE-2026-75021?
High severity. CVSS v3 base score is 8.1 out of 10.