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fix(deps): update dependency @vitest/browser to v5.0.5 [security] (main) - #495

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fix(deps): update dependency @vitest/browser to v5.0.5 [security] (main)#495
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renovate/main-npm-vitest-browser-vulnerability

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@tribble-trouble tribble-trouble Bot commented Oct 22, 2026

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This PR contains the following updates:

Package Change Age Confidence
@vitest/browser (source) 5.0.3 → 5.0.5 age confidence

Vitest: Servers misapply server.fs.deny, serving .env, private keys, .git, and the API token file

CVE-2026-112948 / GHSA-p458-7748-mcp3

More information

Details

Summary

In Vitest 5, Vite's server.fs.deny is not applied as intended on Vitest's dev servers. Depending on the server, files that Vite refuses to serve by default (such as .env, private keys and certificates, .npmrc, and .git) or Vitest's own API token file (.vitest-secret-token) can be read over plain HTTP by a client that can reach the server. In Browser Mode with test.projects, a malicious website can also read .env values through the developer's browser.

This only applies when Vitest runs an HTTP server, which happens with the UI (--ui), Browser Mode, or api enabled. Plain vitest and vitest run don't listen on any port and are not affected. The fix ships in vitest, and @vitest/ui and @vitest/browser are listed because they are what enables the affected setups. Both pin vitest to the same version as a peer dependency, so upgrading either one also requires the patched vitest. Users who enable api without @vitest/ui or @vitest/browser are also affected and should upgrade vitest.

Details

Vitest 5 adds its API token file to server.fs.deny, but neither server ended up with the intended list. That's because of two Vite behaviors. Vite applies its default deny list only when server.fs.deny is unset, and it compiles the list into a matcher during config resolution, so later changes to the array have no effect.

setup listening server Vite's default deny list .vitest-secret-token
plain vitest / vitest run none not reachable not reachable
--ui or api root denied served (fallback location only)
Browser Mode, single project root (also the browser server) denied served (fallback location only)
Browser Mode with test.projects each browser project's server served denied
  • Project servers set deny: ['.vitest-secret-token'] from a config() hook, which replaces Vite's defaults. A project server listens on a port in Browser Mode with test.projects, so in that setup a request like GET /.env?raw returns the file. A plain GET /.env is also served as text/javascript, so a malicious page can include it with <script src="http://localhost:<port>/.env">. A classic script include needs no CORS, and each dotenv line whose value is valid JavaScript (a quoted string, number, or boolean) runs as a global assignment the page can read. A syntax error anywhere in the file, such as a # comment, keeps the whole script from running. The same missing defaults also loosen Browser Mode's file-access checks for server.readFile/writeFile/removeFile, screenshots, and traces.
  • The root server adds the token entry after Vite has compiled the matcher, so the entry is never applied. The token file normally lives in the per-user data directory, which is outside server.fs.allow. When that directory can't be written, for example in a container whose user has no writable HOME, Vitest falls back to <workspaceRoot>/node_modules/.vitest/.vitest-secret-token, which the root server then serves. The token authenticates the UI, /__vitest_attachment__, and the API WebSocket, whose RPC can write and rerun test files when api.allowWrite/api.allowExec are enabled.
Impact

Information disclosure from the Vitest dev server, and with the token, privileged API access.

  • From a malicious website, in Browser Mode with test.projects: while the browser server runs, any page the developer visits can read .env values that are valid JavaScript, through a classic <script> include. This works when the file consists of KEY="value" lines. An unquoted value causes a runtime error that stops the script at that line, so only the lines before it leak. A syntax error anywhere in the file, such as a # comment line or an export prefix, prevents the script from running at all. Recent Chrome versions may ask for Local Network Access permission first. fetch and XHR reads from other websites are still blocked by Vite's default CORS policy, and Vite's Host check blocks DNS rebinding. That CORS policy does allow localhost origins, so a page served from another local dev server could read full files. The token file can't be read through a classic <script>, because a bare token isn't valid JavaScript.
  • With local access or developer-set network exposure (such as api.host or browser.api.host, port forwarding, or a published container port): full file contents are readable over plain HTTP, including the token file when it's in the fallback location.

Only the machine running Vitest is exposed, while it runs one of the setups above. Applications built or deployed from the project aren't affected.

The fix is in vitest <PATCHED>. Vitest 4 and earlier are unaffected. They don't persist an API token, and they don't override server.fs.deny.

Workaround

Set server.fs.deny explicitly in the root Vitest config, including Vite's default list for your Vite version and the token file. For Vite 8.3:

export default defineConfig({
  server: {
    fs: {
      deny: [
        '.env',
        '.env.*',
        '*.{crt,pem,key,p12,pfx,cer,der}',
        '.npmrc',
        '.yarnrc.yml',
        '**/.git/**',
        '.vitest-secret-token',
      ],
    },
  },
})

Severity

  • CVSS Score: 6.5 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

References

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

Release Notes

vitest-dev/vitest (@​vitest/browser)

v5.0.5

Compare Source

   🐞 Bug Fixes
    View changes on GitHub

v5.0.4

Compare Source

   🚀 Features
   🐞 Bug Fixes
   🏎 Performance
    View changes on GitHub

Configuration

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🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

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🔕 Ignore: Close this PR and you won't be reminded about this update again.

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@tribble-trouble

tribble-trouble Bot commented Oct 22, 2026 •
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⚠️ Artifact update problem

Renovate failed to update an artifact related to this branch. You probably do not want to merge this PR as-is.

♻ Renovate will retry this branch, including artifacts, only when one of the following happens:

  • any of the package files in this branch needs updating, or
  • the branch becomes conflicted, or
  • you click the rebase/retry checkbox if found above, or
  • you rename this PR's title to start with "rebase!" to trigger it manually

The artifact failure details are included below:

File name: package-lock.json
npm warn Unknown env config "store". This will error in a future major version of npm. See `npm help npmrc` for supported config options.
npm error code ERESOLVE
npm error ERESOLVE unable to resolve dependency tree
npm error
npm error While resolving: @cplieger/fetch@1.0.0
npm error Found: vitest@5.0.3
npm error node_modules/vitest
npm error   dev vitest@"5.0.3" from the root project
npm error   peer vitest@"5.0.3" from @vitest/browser-playwright@5.0.3
npm error   node_modules/@vitest/browser-playwright
npm error     dev @vitest/browser-playwright@"5.0.3" from the root project
npm error     peerOptional @vitest/browser-playwright@"5.0.3" from vitest@5.0.3
npm error   1 more (@vitest/coverage-v8)
npm error
npm error Could not resolve dependency:
npm error peer vitest@"5.0.5" from @vitest/browser@5.0.5
npm error node_modules/@vitest/browser
npm error   dev @vitest/browser@"5.0.5" from the root project
npm error
npm error Fix the upstream dependency conflict, or retry this command with --force or --legacy-peer-deps to accept an incorrect (and potentially broken) dependency resolution.
npm error
npm error
npm error For a full report see:
npm error /data/base/cache/others/npm/_logs/2026-10-24T16_08_12_746Z-eresolve-report.txt
npm error A complete log of this run can be found in: /data/base/cache/others/npm/_logs/2026-10-24T16_08_12_746Z-debug-0.log

@cplieger cplieger mentioned this pull request Oct 22, 2026
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@tribble-trouble
tribble-trouble Bot force-pushed the renovate/main-npm-vitest-browser-vulnerability branch from e053668 to 21a04e6 Compare October 23, 2026 16:09
@tribble-trouble
tribble-trouble Bot force-pushed the renovate/main-npm-vitest-browser-vulnerability branch from 21a04e6 to e48e648 Compare October 24, 2026 16:08
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