CVE-2026-33943
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.
- CVSS 3.1
- 9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS
- 0.6% chance of exploitation in the next 30 days; higher than 50% of CVEs (scores of 2026-10-25)
- CWEs
- CWE-94, CWE-917
- Published
- Modified
- Record from
- the NVD, synced
Affected
- capricorn86:happy_dom
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-6q6h-j7hj-3r64 | npm | happy-dom | >=15.10.0 <20.8.8 | 20.8.8 |
References
- https://github.com/capricorn86/happy-dom/commit/5437fdf8f13adb9590f9f52616d9f69c3ee8db3c
- https://github.com/capricorn86/happy-dom/releases/tag/v20.8.8
- https://github.com/capricorn86/happy-dom/security/advisories/GHSA-6q6h-j7hj-3r64
- https://access.redhat.com/security/cve/CVE-2026-33943
- https://bugzilla.redhat.com/show_bug.cgi?id=2452522