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HIGHCVE-2026-33943Published Modified CNA GitHub_M

CVE-2026-33943: Happy DOM ECMAScriptModuleCompiler: unsanitized export names are interpolated as executable code

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.

Metrics

CVSS v3.1
8.8
Severity
HIGH
Fixed in
Affected Products
1
Affected packages
  • capricorn86 / happy-dom
    >= 15.10.0, < 20.8.8
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H