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.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
capricorn86 happy-dom
>= 15.10.0, < 20.8.8affected
References
- https://github.com/capricorn86/happy-dom/security/advisories/GHSA-6q6h-j7hj-3r64 ↗
- https://github.com/capricorn86/happy-dom/commit/5437fdf8f13adb9590f9f52616d9f69c3ee8db3c ↗
- https://github.com/capricorn86/happy-dom/releases/tag/v20.8.8 ↗
- https://access.redhat.com/security/cve/CVE-2026-33943 ↗
- https://bugzilla.redhat.com/show_bug.cgi?id=2452522 ↗
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33943.json ↗