CVE-2026-115895

CVE-2026-115895 · Happy DOM: Incomplete fix for CVE-2026-33943: unsanitized import alias leads to host code execution

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Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. From 17.0.0 until 21.0.4, packages/happy-dom/src/module/ECMAScriptModuleCompiler.ts accepts a named ESM import alias without validating that it is a JavaScript binding identifier before inserting it into a generated destructuring binding. With enableJavaScriptEvaluation enabled, attacker-controlled HTML or module source can use an invalid alias that becomes a valid default initializer after compilation, causing the generated JavaScript to execute in the Node.js host process. The demonstrated reachable path uses a JSON module import attribute, which prevents the malicious alias from being emitted again in a later ESM circular-import assignment and keeps the generated function syntactically valid. This incomplete fix for CVE-2026-33943 is a distinct residual path because the earlier remediation validated the local export importName path but not the named-import alias. This issue is fixed in version 21.0.4.

CVSS 8.8 · High · EPSS 0.4% · Public exploit · Fix available

Published

2026-10-23T21:32:24.999Z

Updated

2026-10-23T21:32:24.999Z

Stack: node

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