React Router, a cornerstone library for declarative routing in React applications, has two recent versions available: 7.1.2 and 7.1.3. Both versions maintain the same core dependencies, including "cookie," "turbo-stream," "@types/cookie," and "set-cookie-parser," suggesting no fundamental changes to how the library handles cookies or interacts with Turbo Streams. Similarly, the development dependencies, encompassing tools like "tsup," "react," "rimraf," "wireit," "react-dom," "typescript," and "@types/set-cookie-parser," remain consistent, indicating no significant modifications to the build process or development environment. The peer dependencies also stay identical, requiring React and React DOM versions of at least 18.
A subtle difference emerges in the unpacked size of the distributed package, with version 7.1.3 being marginally larger at 2277376 bytes compared to 7.1.2's 2277325 bytes. This suggests minor code additions, optimizations, or potentially updated assets within the package. Another noticeable change is the release date: version 7.1.3 was published on January 17, 2025, while version 7.1.2 was released on January 16, 2025. Given the close release dates, version 7.1.3 likely addresses bug fixes, performance improvements, or minor feature enhancements identified shortly after the release of its predecessor. Developers should consult the official changelog or release notes for a comprehensive understanding of the specific changes implemented in version 7.1.3. While the differences seem minimal on the surface, it's always recommended to use the latest stable version.
All the vulnerabilities related to the version 7.1.3 of the package
React Router allows pre-render data spoofing on React-Router framework mode
After some research, it turns out that 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. Latest versions are impacted.
The vulnerable header is X-React-Router-Prerender-Data, a specific JSON object must be passed to it in order for the spoofing to be successful as we will see shortly. 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.
Versions used for our PoC:
routes/ssr).data. In our case the page is called /ssr:We access it by adding the suffix .data and retrieve the data object, needed for the header:
X-React-Router-Prerender-Data header with the previously retrieved object as its value. You can change any value of your data object (do not touch the other values, the latter being necessary for the object to be processed correctly and not throw an error):As you can see, all values have been changed/overwritten by the values provided via the header.
The impact is significant, if a cache system is in place, it is possible to poison a response in which all of the data transmitted via a loader would be altered by an attacker allowing him to take control of the content of the page and modify it as he wishes via a cache-poisoning attack. This can lead to several types of attacks including potential stored XSS depending on the context in which the data is injected and/or how the data is used on the client-side.