GitHub Advisoryadvisory · npm

GHSA-qj8w-gfj5-8c6v Serialize JavaScript has CPU Exhaustion Denial of Service via crafted array-like objects

MEDIUM Published 2026-03-27 Modified 2026-05-21 Official page ↗
Aliases
CVE-2026-34043
Ecosystem
npm
Packages
serialize-javascript
Severity
Moderate
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weaknesses
CWE-400, CWE-834
Reviewed
2026-03-27

Affected packages

• npm serialize-javascript: >= 5.0.0, < 7.0.5 → fixed in 7.0.5

Description

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.

Related

Alias · CVE (1)

  • CVE-2026-34043 Serialize JavaScript to a superset of JSON that includes regular expressions and functions. vulnerability

Weakness · CWE (2)

  • CWE-400 Uncontrolled Resource Consumption weakness
  • CWE-834 Excessive Iteration weakness

References