CVE-2026-115895 ยท GHSA-834v-8h66-3h79
Happy DOM: Incomplete fix for CVE-2026-33943: unsanitized import alias leads to host code execution
- Risk score
- 77/100
- CVSS
- 8.8 v3.1
- Exploit chance (30 days)
- 0.6%
- Published
- 23 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it is
- A vulnerability in Happy DOM allows an attacker to execute host code by inserting an unsanitized import alias into a generated destructuring binding. This could lead to code execution in the Node.js host process.
- Affected
- {'products': ['Happy DOM'], 'packages': ['happy-dom'], 'versions': ['>= 17.0.0, <= 21.0.3']}
- Fix
- Upgrade to version 21.0.4 or later
- Exploitation
- Public proof of concept
Why it is Amber
- CVSS 8.8 high
- Public exploit or proof of concept referenced
- Remotely exploitable without logging in
- On your watchlist: npm
Affected packages
| Package | Ecosystem | Vulnerable | Fixed in |
|---|---|---|---|
| happy-dom | npm | >= 17.0.0, <= 21.0.3 | 21.0.4 |
References
- https://github.com/advisories/GHSA-834v-8h66-3h79
- https://github.com/capricorn86/happy-dom/security/advisories/GHSA-834v-8h66-3h79
- https://github.com/capricorn86/happy-dom/pull/2537
- https://github.com/capricorn86/happy-dom/commit/fd163520b74d9fa146be91f7b4e4f46d6cccbe13
- https://github.com/capricorn86/happy-dom/releases/tag/v21.0.4
- https://github.com/advisories/GHSA-834v-8h66-3h79
Original description
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.
Last activity 23 Oct 2026. Patch Forecast updates every hour.