HTTP Request Smuggling Affecting @react-router/express package, versions >=7.0.0 <7.4.1-pre.0
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JS-REACTROUTEREXPRESS-9598036
- published2 Apr 2025
- disclosed1 Apr 2025
- creditRachid Allam, Yasser Allam
Introduced: 1 Apr 2025
CVE-2025-31137 (opens in a new tab)How to fix?
Upgrade @react-router/express to version 7.4.1-pre.0 or higher.
Overview
@react-router/express is an Express server request handler for React Router
Affected versions of this package are vulnerable to HTTP Request Smuggling via Host or X-Forwarded-Host headers. An attacker can spoof the URL used in an incoming request's Host or X-Forwarded-Host header by passing in a URL pathname as the port of a URL.