CVE-2026-112949: Vitest: Code injection via unauthenticated manual mock registration

Description

Vitest is a Vite-native testing framework for JavaScript and TypeScript projects. From 2.1.0-beta.7 until 4.1.12 and 5.0.3, an unauthenticated non-browser WebSocket client that can reach a development server using interceptorPlugin can register a manual mock whose attacker-controlled url createManualModuleSource inserts unescaped into generated module source. When the developer browser loads the affected module, attacker-controlled JavaScript executes on the development-server origin. This issue is fixed in versions 4.1.12 and 5.0.3.

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack vector

Network

Complexity

High

Privileges

None

User interaction

Required

Confidentiality

Low

Integrity

Low

Availability

None

Scope

Changed

Exploitation

Is it being used?

Exploit prediction (EPSS)0.3% · higher than 27% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

MO

mocker · @vitest

>= 2.1.0-beta.7, < 4.1.12; >= 5.0.0, < 5.0.3 · source: vendor

VI

vitest · vitest-dev

>= 2.1.0-beta.7, < 4.1.12; >= 5.0.0, < 5.0.3 · source: vendor