Detect CVE-2026-53633: Vitest Browser Mode API RCE via CDP Proxy and Config Overwrite in Google Chronicle
CVE-2026-53633 is a critical (CVSS 9.8) remote code execution vulnerability in @vitest/browser and vite-plus packages. The browser mode API is exposed without adequate authorization controls (CWE-749, CWE-862), allowing unauthenticated attackers to proxy Chrome DevTools Protocol (CDP) commands and overwrite configuration files. This can lead to arbitrary code execution on the host running Vitest in browser mode. Affected versions include @vitest/browser >= 3.0.0 <= 3.2.4, >= 4.0.0 <= 4.1.7, >= 5.0.0-beta.0 <= 5.0.0-beta.3, and vite-plus <= 0.1.23. A public PoC exists.
MITRE ATT&CK
YARA-L Detection Query
rule vitest_browser_rce_cve_2026_53633 {
meta:
author = "df00tech Detection Engineering"
description = "Detects CVE-2026-53633 exploitation attempts against Vitest browser mode API"
severity = "CRITICAL"
priority = "HIGH"
reference = "https://github.com/vitest-dev/vitest/security/advisories/GHSA-g8mr-85jm-7xhm"
events:
$network.metadata.event_type = "NETWORK_HTTP"
$network.target.port in (51204, 51205, 5173, 5174, 4173)
(
re.regex($network.target.url, `.*(__vitest_api__|__vitest__|/cdp|/json/version|/json/list).*`)
or re.regex($network.network.http.request_url, `.*(__vitest_api__|/cdp|Runtime\.evaluate|Page\.navigate|Target\.attachToTarget).*`)
or re.regex($network.network.http.request_url, `.*\.(env|config\.(js|ts|mjs|cjs)|vitest\.config).*`)
)
condition:
$network
}Chronicle YARA-L rule detecting HTTP requests to Vitest browser mode ports containing CDP API paths, command injection patterns, or config file access URLs associated with CVE-2026-53633.
Data Sources
Required Tables
False Positives & Tuning
- CI systems on Google Cloud running Vitest browser tests against internal services
- Playwright or Puppeteer automation that communicates with Vitest via CDP WebSocket internally
- Developer workstations with Vitest running in browser mode during active development sprints
Other platforms for CVE-2026-53633
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Vitest Browser Mode CDP Discovery via /json Endpoint
Expected signal: HTTP GET requests to /json and /__vitest_api__/ on ports 51204 or 5173 from an external source IP visible in web server or proxy logs
- Test 2CDP Runtime.evaluate Arbitrary JavaScript Execution via Vitest Browser API
Expected signal: WebSocket upgrade request to /devtools/page/<id> followed by CDP Runtime.evaluate method in request payload visible in network capture
- Test 3Vitest Config File Overwrite via Exposed API
Expected signal: HTTP POST to /__vitest_api__ with writeFile method in request body; filesystem audit log showing vitest.config.ts modification timestamp updated outside normal developer hours
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