---
title: "fastify — CVE-2026-84428"
description: "A security flaw affects the npm package fastify. Affected versions: < 5.12.2. Fixed from version 5.12.2. CVSS score 7.5."
canonical: https://inyourgeek.com/en/failles-de-securite/2026-09-30-cve-2026-84428
type: faille-de-securite
author: "Sébastien Soulier"
publisher: "InYourGeek"
language: en
datePublished: 2026-09-30
dateModified: 2026-09-30
---
# fastify — CVE-2026-84428

A security flaw affects the npm package fastify. Affected versions: < 5.12.2. Fixed from version 5.12.2. CVSS score 7.5.

## What to do

Update fastify to 5.12.2 or later.

| Fact | Value |
| --- | --- |
| Package | fastify |
| Ecosystem | npm (JavaScript) |
| Class | Other |
| Affected versions | < 5.12.2 |
| Fixed version | 5.12.2 |
| CVSS | 7.5 |
| CVE | CVE-2026-84428 |
| GHSA | GHSA-9q9j-q6p8-xq58 |
| Published on | September 30, 2026 |
| Severity | High |

## Sources

- [GitHub Security Advisory — GHSA-9q9j-q6p8-xq58](https://github.com/advisories/GHSA-9q9j-q6p8-xq58) — GitHub Security Advisories
- [NVD — CVE-2026-84428](https://nvd.nist.gov/vuln/detail/CVE-2026-84428) — NVD

---

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