CVE-2025-31125: Vite has a `server.fs.deny` bypassed for `inline` and `raw` with `?import` query

Summary

The contents of arbitrary files can be returned to the browser.

Impact

Only apps explicitly exposing the Vite dev server to the network (using --host or server.host config option) are affected.

Details

• base64 encoded content of non-allowed files is exposed using ?inline&import (originally reported as ?import&?inline=1.wasm?init)
• content of non-allowed files is exposed using ?raw?import

/@fs/ isn't needed to reproduce the issue for files inside the project root.

PoC

Original report (check details above for simplified cases):

The ?import&?inline=1.wasm?init ending allows attackers to read arbitrary files and returns the file content if it exists. Base64 decoding needs to be performed twice

$ npm create vite@latest
$ cd vite-project/
$ npm install
$ npm run dev

Example full URL http://localhost:5173/@fs/C:/windows/win.ini?import&?inline=1.wasm?init