Arbitrary JavaScript Execution via otelCarrier in Vitest Browser Mode <4.1.6
CVE-2026-47428 Published on July 14, 2026
Vitest browser mode serves unsanitized otelCarrier query parameter as inline script
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.
Vulnerability Analysis
CVE-2026-47428 is exploitable with network access, requires user interaction. This vulnerability is considered to have a low attack complexity. Public availability of a proof of concept (POC) exploit exists for CVE-2026-47428. The potential impact of an exploit of this vulnerability is considered to be critical as this vulnerability has a high impact to the confidentiality, integrity and availability of this component.
Weakness Type
What is a XSS Vulnerability?
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
CVE-2026-47428 has been classified to as a XSS vulnerability or weakness.
Affected Versions
vitest-dev vitest:- Version >= 4.0.17, < 4.1.6 is affected.
- Version >= 5.0.0-beta.0, < 5.0.0-beta.3 is affected.