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

Advisory record · `GHSA-g8mr-85jm-7xhm`

- **Identifiers:** `GHSA-g8mr-85jm-7xhm` · `CVE-2026-53633`
- **State:** Confirmed
- **Severity:** CVSS 9.8 Critical
- **Critical:** Yes: CVSS 9+
- **Weakness (CWE):** [CWE-749](https://cwe.mitre.org/data/definitions/749.html) · [CWE-862](https://cwe.mitre.org/data/definitions/862.html)
- **Tags:** [Broken access control](https://agentprime.io/advisories/tag/access-control.md) · [CWE-749](https://agentprime.io/advisories/tag/cwe-749.md)
- **Published:** 15 Jun 2026
- **Updated:** 13 Aug 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 15 Jun 2026, 20:05 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Critical

Critical, because:

- CVSS score 9.8: 9.0 or more.

How we decide what’s critical: <https://agentprime.io/advisories/critical.md>

## Affected packages

- `@vitest/browser` (npm): affected `>=5.0.0-beta.0, <5.0.0-beta.4 || >=4.0.0, <4.1.8 || >=3.0.0, <3.2.5`; fixed in `5.0.0-beta.4`, `4.1.8`, `3.2.5`
- `vite-plus` (npm): affected `<0.1.24`; fixed in `0.1.24`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 9.8 Critical, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0090, the 59th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the GitHub Advisory Database, published 15 Jun 2026. New records show when each source confirmed them.

## Sources

- [GitHub Advisory Database: GHSA-g8mr-85jm-7xhm](https://github.com/advisories/GHSA-g8mr-85jm-7xhm)
- [OSV: GHSA-g8mr-85jm-7xhm](https://osv.dev/vulnerability/GHSA-g8mr-85jm-7xhm)
- <https://github.com/vitest-dev/vitest/security/advisories/GHSA-g8mr-85jm-7xhm>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-53633>
- <https://github.com/vitest-dev/vitest/pull/10444>
- <https://github.com/vitest-dev/vitest/pull/10450>
- <https://github.com/vitest-dev/vitest/pull/10456>
- <https://github.com/vitest-dev/vitest/commit/385a1aefd4c2bfa5e7d58bf7c6834c929969f2c7>
- <https://github.com/vitest-dev/vitest/commit/63e3b2eee4d58da56786a6333f517b9b492528c7>
- <https://github.com/vitest-dev/vitest/commit/e4067b3b150005fd42cf75f994300119245806b9>
- <https://github.com/vitest-dev/vitest>
- <https://github.com/vitest-dev/vitest/releases/tag/v3.2.5>
- <https://github.com/vitest-dev/vitest/releases/tag/v4.1.8>
- <https://github.com/vitest-dev/vitest/releases/tag/v5.0.0-beta.4>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-g8mr-85jm-7xhm>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

---

The web page: <https://agentprime.io/advisories/GHSA-g8mr-85jm-7xhm/>. Everything for agents: <https://agentprime.io/llms.txt>.