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CVE-2026-33943— Happy DOM ECMAScriptModuleCompiler: unsanitized export names are interpolated as executable code

Quick assessment

Affected
capricorn86 happy-dom
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

happy-dom是David Ortner个人开发者的一种没有图形用户界面的 web 浏览器的 JavaScript 实现。 happy-dom 20.8.7及之前版本存在代码注入漏洞，该漏洞源于ECMAScriptModuleCompiler存在代码注入问题，可能导致攻击者通过注入任意JavaScript表达式实现远程代码执行。

CVSS 8.8 · High EPSS 0.97% · P61

Affected Version Matrix 1

VendorProduct Version RangeStatus
capricorn86 happy-dom >= 15.10.0, < 20.8.8 affected
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I. Basic Information for CVE-2026-33943

Vulnerability Information
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Vulnerability Title
Happy DOM ECMAScriptModuleCompiler: unsanitized export names are interpolated as executable code
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
对生成代码的控制不恰当(代码注入)
Source: CVE Program / CVE List V5
Vulnerability Title
happy-dom 代码注入漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
happy-dom是David Ortner个人开发者的一种没有图形用户界面的 web 浏览器的 JavaScript 实现。 happy-dom 20.8.7及之前版本存在代码注入漏洞，该漏洞源于ECMAScriptModuleCompiler存在代码注入问题，可能导致攻击者通过注入任意JavaScript表达式实现远程代码执行。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
capricorn86 happy-dom >= 15.10.0, < 20.8.8 -

II. Public POCs for CVE-2026-33943

# POC Description Source Link Shenlong Link
AI-Generated POC Premium
Qwen3.6-35B-A3B · 9709 chars
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In-depth vulnerability mechanism
Trigger conditions & impact
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III. Intelligence Information for CVE-2026-33943

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Patches & Fixes for CVE-2026-33943 (1)

Vendor Advisories for CVE-2026-33943 (1)

Vendor Pages for CVE-2026-33943 (1)

IV. Related Vulnerabilities

Same product: happy-dom
Same vendor: capricorn86
Same weakness: CWE-94

V. Comments for CVE-2026-33943

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