---
title: "CVE-2026-53633: Vitest Browser: Exposed Browser Mode API Can Proxy CDP and Overwrite Config Files, Leading to RCE"
url: https://erroneo.us/security/cve/CVE-2026-53633/
description: "CVE-2026-53633 (@vitest/browser (npm)): Vitest is a testing framework powered by Vite. From 3.0.0 until 3.2.5, 4.1.8, and 5.0.0-beta.4, Vitest Browser Mode…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-07-14
date_modified: 2026-08-13
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-53633"
kev: false
cvss: 9.8
epss: 0.00896
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-53633: Vitest Browser: Exposed Browser Mode API Can Proxy CDP and Overwrite Config Files, Leading to RCE

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.9% , percentile 59: FIRST’s model estimates a 0.9% chance of exploitation activity in the next 30 days, higher than 59% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes @vitest/browser (npm) >= 5.0.0-beta.0, <= 5.0.0-beta.3, fixed in 5.0.0-beta.4 ; @vitest/browser (npm) >= 4.0.0, <= 4.1.7, fixed in 4.1.8 ; @vitest/browser (npm) >= 3.0.0, <= 3.2.4, fixed in 3.2.5 ; vite-plus (npm) <= 0.1.23, fixed in 0.1.24 . Check your lockfile, including transitive dependencies.

## What it is

Vitest is a testing framework powered by Vite. From 3.0.0 until 3.2.5, 4.1.8, and 5.0.0-beta.4, Vitest Browser Mode exposed a cdp() API that forwarded raw Chrome DevTools Protocol methods without being gated by allowWrite or allowExec, allowing a remote client with exposed browser API metadata to use CDP Page.setDownloadBehavior and Runtime.evaluate to overwrite vite.config.ts and execute attacker-controlled Node.js code. This issue is fixed in versions 3.2.5, 4.1.8, and 5.0.0-beta.

## Affected packages

- npm `@vitest/browser` >= 5.0.0-beta.0, <= 5.0.0-beta.3 → fixed: 5.0.0-beta.4
- npm `@vitest/browser` >= 4.0.0, <= 4.1.7 → fixed: 4.1.8
- npm `@vitest/browser` >= 3.0.0, <= 3.2.4 → fixed: 3.2.5
- npm `vite-plus` <= 0.1.23 → fixed: 0.1.24

## Affected products (CVE record)

- vitest-dev vitest: >= 3.0.0, < 3.2.5, >= 4.0.0, < 4.1.8, >= 5.0.0-beta.0, < 5.0.0-beta.4

## Severity

- GitHub_M CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.90% probability of exploitation activity in the next 30 days; percentile 59.

## Sources

- [GitHub Advisory GHSA-g8mr-85jm-7xhm](https://github.com/advisories/GHSA-g8mr-85jm-7xhm)
- [CVE.org record CVE-2026-53633](https://www.cve.org/CVERecord?id=CVE-2026-53633)
- [NVD entry CVE-2026-53633](https://nvd.nist.gov/vuln/detail/CVE-2026-53633)
- [github.com](https://github.com/vitest-dev/vitest/security/advisories/GHSA-g8mr-85jm-7xhm)
- [github.com](https://github.com/vitest-dev/vitest/pull/10444)
- [github.com](https://github.com/vitest-dev/vitest/pull/10450)
- [github.com](https://github.com/vitest-dev/vitest/pull/10456)
- [github.com](https://github.com/vitest-dev/vitest/commit/385a1aefd4c2bfa5e7d58bf7c6834c929969f2c7)
- [github.com](https://github.com/vitest-dev/vitest/commit/63e3b2eee4d58da56786a6333f517b9b492528c7)
- [github.com](https://github.com/vitest-dev/vitest/commit/e4067b3b150005fd42cf75f994300119245806b9)
- [github.com](https://github.com/vitest-dev/vitest/releases/tag/v3.2.5)
- [github.com](https://github.com/vitest-dev/vitest/releases/tag/v4.1.8)
- [github.com](https://github.com/vitest-dev/vitest/releases/tag/v5.0.0-beta.4)

---
Source page: https://erroneo.us/security/cve/CVE-2026-53633/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt