CVE-2026-112949
Received
Received - Intake
Unauthenticated JavaScript Execution in Vitest via WebSocket
Vulnerability report for CVE-2026-112949, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-10-20
Last updated on: 2026-10-20
Assigner: GitHub, Inc.
Description
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 Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| vitest-dev | vitest | >= 2.1.0-beta.7, < 4.1.12 |
| vitest-dev | vitest | >= 5.0.0, < 5.0.3 |
| @vitest | mocker | >= 2.1.0-beta.7, < 4.1.12 |
| @vitest | mocker | >= 5.0.0, < 5.0.3 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-306 | The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources. |
| CWE-116 | The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved. |
| CWE-94 | The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. |
