{"cve":"CVE-2026-33943","nvd":{"published":"2026-03-27T22:16:21.393","modified":"2026-10-26T00:10:00.150","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-94","CWE-917"],"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"],"products":["capricorn86:happy_dom"],"source":"nvd","synced_at":"2026-10-26T00:31:35.753532240+00:00"},"epss":{"cve":"CVE-2026-33943","score":0.00646,"percentile":0.50681,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-6q6h-j7hj-3r64","url":"https://osv.dev/vulnerability/GHSA-6q6h-j7hj-3r64","summary":"Happy DOM ECMAScriptModuleCompiler: unsanitized export names are interpolated as executable code","modified":"2026-03-30T20:16:18.541434Z","packages":[{"ecosystem":"npm","name":"happy-dom","purl":"pkg:npm/happy-dom","ranges":[">=15.10.0 <20.8.8"],"fixed":["20.8.8"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}