GHSA-444r-cwp2-x5xf

Source

https://github.com/advisories/GHSA-444r-cwp2-x5xf

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-444r-cwp2-x5xf/GHSA-444r-cwp2-x5xf.json

JSON Data

https://api.osv.dev/v1/vulns/GHSA-444r-cwp2-x5xf

Aliases

CVE-2026-3635

Published

2026-03-25T19:32:28Z

Modified

2026-03-25T19:48:38.788319Z

Severity

6.1 (Medium) CVSS_V3 - CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N CVSS Calculator

Summary

fastify: request.protocol and request.host Spoofable via X-Forwarded-Proto/Host from Untrusted Connections

Details

Summary

When trustProxy is configured with a restrictive trust function (e.g., a specific IP like trustProxy: '10.0.0.1', a subnet, a hop count, or a custom function), the request.protocol and request.host getters read X-Forwarded-Proto and X-Forwarded-Host headers from any connection — including connections from untrusted IPs. This allows an attacker connecting directly to Fastify (bypassing the proxy) to spoof both the protocol and host seen by the application.

Affected Versions

fastify <= 5.8.2

Impact

Applications using request.protocol or request.host for security decisions (HTTPS enforcement, secure cookie flags, CSRF origin checks, URL construction, host-based routing) are affected when trustProxy is configured with a restrictive trust function.

When trustProxy: true (trust everything), both host and protocol trust all forwarded headers — this is expected behavior. The vulnerability only manifests with restrictive trust configurations.

Database specific

{
    "github_reviewed": true,
    "cwe_ids": [
        "CWE-348"
    ],
    "nvd_published_at": "2026-03-23T14:16:34Z",
    "github_reviewed_at": "2026-03-25T19:32:28Z",
    "severity": "MODERATE"
}

References

Affected packages

npm / fastify

Package

Name: fastify; View open source insights on deps.dev
Purl: pkg:npm/fastify

Affected ranges

Type: SEMVER
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

5.8.3

Database specific

last_known_affected_version_range

"<= 5.8.2"

source

"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-444r-cwp2-x5xf/GHSA-444r-cwp2-x5xf.json"