fastify vulnerable to X-Forwarded-* spoofing under trustProxy hop-count — GHSA-3M5P-2C4R-XXW2

Summary

## Impact The fix for [CVE-2026-3635](https://www.cve.org/CVERecord?id=CVE-2026-3635) ([GHSA-444r-cwp2-x5xf](https://github.com/fastify/fastify/security/advisories/GHSA-444r-cwp2-x5xf)) added a `proxyFn(socket.remoteAddress, 0)` guard on the `X-Forwarded-*` reads in `request.host`, `request.protocol`, `request.hostname`, `request.ip`, and `request.ips`. That guard closes the IP, CIDR, and custom-function forms of…

Timeline

Published by source

2026-09-02

Risk context

• Reported severity or threat level: medium.
• Reported CVSS score: 6.1 out of 10.
• Reported EPSS value: 0.00144.
• Review exposure for the affected product or family: npm: fastify.

Product

npm: fastify

What to do

General, cautious steps (verify details in the official source):

• Review exposure and plan remediation based on risk and environment.
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

Evidence and provenance

Canonical advisory ID

GHSA-3M5P-2C4R-XXW2

Source

GitHub

Vendor

GitHub

Published by source

2026-09-02

Last source activity

2026-09-02

Additional identifiers

CVE-2026-16732

Curated by

hlukh.ch

Related advisories and connections

These advisories are connected by shared CVE, product, vendor, source, or time signals.