Vitest is a testing framework powered by Vite. The `__screenshot-error` handler on the browser mode HTTP server that responds any file on the file system. Especially if the server is exposed on the network by `browser.api.host: true`, an attacker can send a request to that handler from remote to get the content of arbitrary files.This `__screenshot-error` handler on the browser mode HTTP server responds any file on the file system. This code was added by commit `2d62051`. Users explicitly exposing the browser mode server to the network by `browser.api.host: true` may get any files exposed. This issue has been addressed in versions 2.1.9 and 3.0.4. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Affected: npm: @vitest/browser

### Summary `__screenshot-error` handler on the browser mode HTTP server that responds any file on the file system. Especially if the server is exposed on the network by [`browser.api.host: true`](https://vitest.dev/guide/browser/config.html#browser-api), an attacker can send a request to that handler from remote to get the content of arbitrary files.

### Details This `__screenshot-error` handler on the browser mode HTTP server responds any file on the file system. https://github.com/vitest-dev/vitest/blob/f17918a79969d27a415f70431e08a9445b051e45/packages/browser/src/node/plugin.ts#L88-L130

This code was added by https://github.com/vitest-dev/vitest/commit/2d62051f13b4b0939b2f7e94e88006d830dc4d1f.

### PoC 1. Create a directory and change the current directory to that directory 1. Run `npx vitest init browser` 1. Run `npm run test:browser` 2. Run `curl http://localhost:63315/__screenshot-error?file=/path/to/any/file`

### Impact Users explicitly exposing the browser mode server to the network by [`browser.api.host: true`](https://vitest.dev/guide/browser/config.html#browser-api) may get any files exposed.