Remix and React Router allow URL manipulation via Host / X-Forwarded-Host headers
Impact
We received a report about a vulnerability in Remix/React Router that affects all Remix 2 and React Router 7 consumers using the Express adapter. Basically, this vulnerability allows anyone to spoof the URL used in an incoming Request by putting a URL pathname in the port section of a URL that is part of a Host or X-Forwarded-Host header sent to a Remix/React Router request handler.
Patches
This issue has been patched and released in Remix 2.16.3 React Router 7.4.1.
Credits
- Rachid Allam (zhero;)
- Yasser Allam (inzo_)
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | @react-router/express | >= 7.0.0, < 7.4.1 | 7.4.1 |
| npm package | @remix-run/express | >= 2.11.1, < 2.16.3 | 2.16.3 |
References
- CVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-444- Platform
- npm
- Package
@react-router/express, @remix-run/express- Disclosed
- 01.04.2025
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-4q56-crqp-v477 - CC BY 4.0
Vulnerability history: @remix-run/express
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
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