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

> Attackers can execute arbitrary JavaScript in Vitest Browser Mode via unsanitized query parameters, potentially stealing API tokens.

- **Severity:** Critical 9.6 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 14 Jul 2026
- **Updated:** 15 Jul 2026
- **Also known as:** GHSA-2h32-95rg-cppp, MINI-2jrf-q37h-x2x3, MINI-4rr3-8c8r-v8h2

## What is CVE-2026-47428?

CVE-2026-47428 is a critical cross-site scripting vulnerability in vitest-dev vitest, published on 14 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-47428?

4 open source packages ship an affected version, including @vitest/browser.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `@vitest/browser` | npm | From 4.0.17 | 4.1.6 |
| `@vitest/browser` | npm | From 4.0.17 | 4.1.6 |
| `@vitest/browser` | npm | From 5.0.0-beta.0 | 5.0.0-beta.3 |
| `@vitest/browser` | npm | From 5.0.0-beta.0 | 5.0.0-beta.3 |

## How do I fix CVE-2026-47428?

Upgrade @vitest/browser to a fixed version for your release line: 4.1.6 or 5.0.0-beta.3.

## Is CVE-2026-47428 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-47428 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-47428 and fix it if it is affected.

What it is: CVE-2026-47428 is a critical cross-site scripting vulnerability in vitest-dev vitest, published on 14 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-47428 exists.

Affected packages and fixed versions:
- @vitest/browser (npm): affected from 4.0.17; fixed in 4.1.6
- @vitest/browser (npm): affected from 4.0.17; fixed in 4.1.6
- @vitest/browser (npm): affected from 5.0.0-beta.0; fixed in 5.0.0-beta.3
- @vitest/browser (npm): affected from 5.0.0-beta.0; fixed in 5.0.0-beta.3

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-47428/ (Markdown: https://insights.sbomify.com/CVE-2026-47428/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-47428
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-47428
- OSV: https://osv.dev/vulnerability/CVE-2026-47428

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-47428/
Summaries are generated and may contain mistakes; the official description above is the record.