CVE-2026-33943
CRITICAL WAF: Medium
CVSS 9.8
Published: 2026-03-27
CWE-94
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.
WAF Coverage Analysis
Code Injection
Medium WAF Coverage
OWASP: A03:2021 Injection
932xxx - Remote Code Execution 933xxx - PHP Injection 934xxx - Node.js / Generic Injection
Affected Software
| Vendor | Product | Version |
|---|---|---|
| capricorn86 | happy_dom | 15.10.0 - 20.8.8 |
References
- github.com (Patch)
- github.com (Product, Release Notes)
- github.com (Exploit, Vendor Advisory)