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CVE-2026-33943

HIGH

8.8

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.

CVE Details

CVSS v3.1 Score8.8

SeverityHIGH

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionREQUIRED

Published3/27/2026

Last Modified3/30/2026

Sourcenvd

Honeypot Sightings0

Weaknesses (CWE)

CWE-94

References

https://github.com/capricorn86/happy-dom/commit/5437fdf8f13adb9590f9f52616d9f69c3ee8db3c(security-advisories@github.com)

https://github.com/capricorn86/happy-dom/releases/tag/v20.8.8(security-advisories@github.com)

https://github.com/capricorn86/happy-dom/security/advisories/GHSA-6q6h-j7hj-3r64(security-advisories@github.com)

https://github.com/capricorn86/happy-dom/security/advisories/GHSA-6q6h-j7hj-3r64(134c704f-9b21-4f2e-91b3-4a467353bcc0)

IOC Correlations

No correlations recorded

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