CVE-2025-43865 React Router allows pre-render data spoofing on React-Router framework mode
Attackers can spoof pre-rendered data in React Router framework mode by manipulating request headers, requiring specific configuration to exploit.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-43865?
CVE-2025-43865 is a high-severity vulnerability in remix-run react-router, published on 25 Apr 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
React Router is a router for React. In versions on the 7.0 branch prior to version 7.5.2, it's possible to modify pre-rendered data by adding a header to the request. This allows to completely spoof its contents and modify all the values of the data object passed to the HTML. This issue has been patched in version 7.5.2.
Weakness: CWE-345
Which versions are affected by CVE-2025-43865?
2 open source packages ship an affected version, including react-router.
| Package | Affected | Fixed in |
|---|---|---|
react-router npm | From 7.0.0-pre.0 | 7.5.2 |
react-router npm | From 7.0.0-pre.0 | 7.5.2 |
How do I fix CVE-2025-43865?
Upgrade react-router to 7.5.2 or later.
Is CVE-2025-43865 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-43865 exists.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as GHSA-cpj6-fhp6-mr6j.