PT-2026-28574 · Happy-Dom · Happy-Dom

Tndud042713 · Published 2026-03-26 · Updated 2026-03-31 · CVE-2026-33943

Positive Technologies (AI Summary)

CVSS v3.1

9.8

Critical

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions Happy DOM versions 15.10.0 through 20.8.7

Description Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Versions 15.10.0 through 20.8.7 contain a code injection issue in the ECMAScriptModuleCompiler component. This 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. The quote filter does not strip backticks, allowing template literal-based payloads to bypass sanitization.

Recommendations Update to version 20.8.8 to resolve the issue.

Exploit

Fix

Code Injection

Weakness Enumeration

CWE-94

Related Identifiers

CVE-2026-33943

GHSA-6Q6H-J7HJ-3R64

Affected Products

Happy-Dom

References · 14

• 🔥 https://github.com/capricorn86/happy-dom/security/advisories/GHSA-6q6h-j7hj-3r64 · Exploit
• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33943.json · Exploit
• https://github.com/capricorn86/happy-dom/commit/5437fdf8f13adb9590f9f52616d9f69c3ee8db3c · Patch
• https://osv.dev/vulnerability/CVE-2026-33943 · Vendor Advisory
• https://osv.dev/vulnerability/GHSA-6q6h-j7hj-3r64 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-33943 · Security Note
• https://github.com/capricorn86/happy-dom · Note
• https://github.com/capricorn86/happy-dom/releases/tag/v20.8.8 · Note
• https://reddit.com/r/VulnMatter/comments/1s55ox2/resumen_diario_de_vulnerabilidades_27032026 · Reddit Post
• https://twitter.com/CVEnew/status/2037719369304949069 · Twitter Post
• https://twitter.com/pulsepatchio/status/2038998087511793802 · Twitter Post
• https://reddit.com/r/VulnMatter/comments/1s5634y/resumen_diario_de_vulnerabilidades_27032026 · Reddit Post
• https://twitter.com/TheHackerWire/status/2037665954944237642 · Twitter Post
• https://twitter.com/CveFindCom/status/2037661704662790651 · Twitter Post