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Description

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.

PUBLISHED Reserved 2026-03-24 | Published 2026-03-27 | Updated 2026-03-27 | Assigner GitHub_M




HIGH: 8.8CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Problem types

CWE-94: Improper Control of Generation of Code ('Code Injection')

Product status

>= 15.10.0, < 20.8.8
affected

References

github.com/...py-dom/security/advisories/GHSA-6q6h-j7hj-3r64 exploit

github.com/...py-dom/security/advisories/GHSA-6q6h-j7hj-3r64

github.com/...ommit/5437fdf8f13adb9590f9f52616d9f69c3ee8db3c

github.com/capricorn86/happy-dom/releases/tag/v20.8.8

cve.org (CVE-2026-33943)

nvd.nist.gov (CVE-2026-33943)

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