CVE-2026-33943
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.
How to fix
- capricorn86 happy_dom20.8.8 or later
- happy-dom20.8.8 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| capricorn86 happy_dom | 15.10.0 ≤ v < 20.8.8 | 20.8.8 |
| happy-domnpm | 15.10.0 ≤ v < 20.8.8 | 20.8.8 |
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Attack Surface Management
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