CVE-2026-33943

Updated on 27 Mar 2026

Severity

9.8 Critical severity

Details

CVSS score
9.8
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Overview

About vulnerability

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. In versions 15.10.0 through 20.8.7, a code injection vulnerability in ECMAScriptModuleCompiler allows an attacker to achieve Remote Code Execution (RCE) by injecting arbitrary JavaScript expressions inside export { } declarations in ES module scripts processed by happy-dom. The compiler directly interpolates unsanitized content into generated code as an executable expression, and the quote filter does not strip backticks, allowing template literal-based payloads to bypass sanitization. Version 20.8.8 fixes the issue.

Details

Affected product:
happy-dom
Affected packages:
happy-dom @ 9.10.9
Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. In versions 15.10.0 through 20.8.7, a code injection vulnerability in ECMAScriptModuleCompiler allows an attacker to achieve Remote Code Execution (RCE) by injecting arbitrary JavaScript expressions inside export { } declarations in ES module scripts processed by happy-dom. The compiler directly interpolates unsanitized content into generated code as an executable expression, and the quote filter does not strip backticks, allowing template literal-based payloads to bypass sanitization. Version 20.8.8 fixes the issue.