Improper Control of Generation of Code ('Code Injection')
CVE-2026-115895
Summary
Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. In versions 17.0.0 prior to 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.
- LOW
- NETWORK
- HIGH
- UNCHANGED
- REQUIRED
- NONE
- HIGH
- HIGH
CWE-94 - Code Injection
Code injection is a type of vulnerability that allows an attacker to execute arbitrary code. This vulnerability fully compromises the machine and can cause a wide variety of security issues, such as unauthorized access to sensitive information, manipulation of data, denial of service attacks etc. Code injection is different from command injection in the fact that it is limited by the functionality of the injected language (e.g. PHP), as opposed to command injection, which leverages existing code to execute commands, usually within the context of a shell.
References
Advisory Timeline
- Published
