{"id":"CVE-2026-33943","aliases":["GHSA-6q6h-j7hj-3r64"],"url":"https://o3.security/vulnerability/CVE-2026-33943","summary":"Happy DOM ECMAScriptModuleCompiler: unsanitized export names are interpolated as executable code","details":"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.","published":"2026-03-27T21:15:19.186Z","modified":"2026-08-12T03:51:43.166166528Z","cvss":{"score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"happy-dom","fixedVersion":"20.8.8"}],"fix":{"url":"https://github.com/capricorn86/happy-dom/commit/5437fdf8f13adb9590f9f52616d9f69c3ee8db3c","label":"capricorn86/happy-dom@5437fdf"},"references":[{"type":"WEB","url":"https://github.com/capricorn86/happy-dom/releases/tag/v20.8.8"},{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33943.json"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-33943"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33943.json"},{"type":"ADVISORY","url":"https://github.com/capricorn86/happy-dom/security/advisories/GHSA-6q6h-j7hj-3r64"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33943"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2452522"},{"type":"FIX","url":"https://github.com/capricorn86/happy-dom/commit/5437fdf8f13adb9590f9f52616d9f69c3ee8db3c"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:43.166166528Z"}}