GHSA-f46r-rw29-r322

Source

https://github.com/advisories/GHSA-f46r-rw29-r322

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/04/GHSA-f46r-rw29-r322/GHSA-f46r-rw29-r322.json

JSON Data

https://api.osv.dev/v1/vulns/GHSA-f46r-rw29-r322

Aliases

CVE-2025-43864

Published

2025-04-24T16:31:16Z

Modified

2025-04-25T14:32:54Z

Severity

7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator

Summary

React Router allows a DoS via cache poisoning by forcing SPA mode

Details

Summary

After some research, it turns out that it is possible to force an application to switch to SPA mode by adding a header to the request. If the application uses SSR and is forced to switch to SPA, this causes an error that completely corrupts the page. If a cache system is in place, this allows the response containing the error to be cached, resulting in a cache poisoning that strongly impacts the availability of the application.

Details

The vulnerable header is X-React-Router-SPA-Mode; adding it to a request sent to a page/endpoint using a loader throws an error. Here is the vulnerable code :

To use the header, React-router must be used in Framework mode, and for the attack to be possible the target page must use a loader.

Steps to reproduce

Versions used for our PoC: - "@react-router/node": "^7.5.0", - "@react-router/serve": "^7.5.0", - "react": "^19.0.0" - "react-dom": "^19.0.0" - "react-router": "^7.5.0"

Install React-Router with its default configuration in Framework mode (https://reactrouter.com/start/framework/installation)
Add a simple page using a loader (example: routes/ssr)

Send a request to the endpoint using the loader (/ssr in our case) adding the following header:
```
X-React-Router-SPA-Mode: yes
```

Notice the difference between a request with and without the header;

Normal request Capture d’écran 2025-04-07 à 08 36 27

With the header Capture d’écran 2025-04-07 à 08 37 01

Impact

If a system cache is in place, it is possible to poison the response by completely altering its content (by an error message), strongly impacting its availability, making the latter impractical via a cache-poisoning attack.

Credits

Rachid Allam (zhero;)
Yasser Allam (inzo_)

Database specific

{
    "nvd_published_at": "2025-04-25T01:15:43Z",
    "cwe_ids": [
        "CWE-755"
    ],
    "severity": "HIGH",
    "github_reviewed": true,
    "github_reviewed_at": "2025-04-24T16:31:16Z"
}

References

Affected packages

npm / react-router

Package

Name: react-router; View open source insights on deps.dev
Purl: pkg:npm/react-router

Affected ranges

Type: SEMVER
Events: Introduced

7.2.0

Fixed

7.5.2

Database specific

{
    "last_known_affected_version_range": "<= 7.5.1"
}