Vulnerability Instance

Serialize JavaScript has CPU Exhaustion Denial of Service via crafted array-like objects
### Impact

**What kind of vulnerability is it?**

It is a **Denial of Service (DoS)** vulnerability caused by CPU exhaustion. When serializing a specially crafted "array-like" object (an object that inherits from `Array.prototype` but has a very large `length` property), the process enters an intensive loop that consumes 100% CPU and hangs indefinitely.

**Who is impacted?**

Applications that use `serialize-javascript` to serialize untrusted or user-controlled objects are at risk. While direct exploitation is difficult, it becomes a high-priority threat if the application is also vulnerable to **Prototype Pollution** or handles untrusted data via **YAML Deserialization**, as these could be used to inject the malicious object.

### Patches

**Has the problem been patched?**

Yes, the issue has been patched by replacing `instanceof Array` checks with `Array.isArray()` and using `Object.keys()` for sparse array detection.

**What versions should users upgrade to?**

Users should upgrade to **`v7.0.5`** or later.

### Workarounds

**Is there a way for users to fix or remediate the vulnerability without upgrading?**

There is no direct code-level workaround within the library itself. However, users can mitigate the risk by:

* Validating and sanitizing all input before passing it to the `serialize()` function.
* Ensuring the environment is protected against Prototype Pollution.
* Upgrading to **`v7.0.5`** as soon as possible.

### Acknowledgements

Serialize JavaScript thanks **Tomer Aberbach** (@TomerAberbach) for discovering and privately disclosing this issue.