CVE-2025-31486: Vite allows server.fs.deny to be bypassed with .svg or relative paths

### 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](https://vitejs.dev/config/server-options.html#server-host)) are affected. ### Details #### `.svg` Requests ending with `.svg` are loaded at this line. https://github.com/vitejs/vite/blob/037f801075ec35bb6e52145d659f71a23813c48f/packages/vite/src/node/plugins/asset.ts#L285-L290 By adding `?.svg` with `?.wasm?init` or with `sec-fetch-dest: script` header, the restriction was able to bypass. This bypass is only possible if the file is smaller than [`build.assetsInlineLimit`](https://vite.dev/config/build-options.html#build-assetsinlinelimit) (default: 4kB) and when using Vite 6.0+. #### relative paths The check was applied before the id normalization. This allowed requests to bypass with relative paths (e.g. `../../`). ### PoC ```bash npm create vite@latest cd vite-project/ npm install npm run dev ``` send request to read `etc/passwd` ```bash curl 'http://127.0.0.1:5173/etc/passwd?.svg?.wasm?init' ``` ```bash curl 'http://127.0.0.1:5173/@fs/x/x/x/vite-project/?/../../../../../etc/passwd?import&?raw' ```