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
v7.0.5as soon as possible.
Acknowledgements
Serialize JavaScript thanks Tomer Aberbach (@TomerAberbach) for discovering and privately disclosing this issue.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | serialize-javascript | >= 5.0.0, < 7.0.5 | 7.0.5 |
References
- https://github.com/yahoo/serialize-javascript/security/advisories/GHSA-qj8w-gfj5-8c6v
- https://nvd.nist.gov/vuln/detail/CVE-2026-34043
- https://github.com/yahoo/serialize-javascript/commit/f147e90269b58bb6e539cfdf3d0e20d6ad14204b
- https://github.com/yahoo/serialize-javascript
- https://github.com/yahoo/serialize-javascript/releases/tag/v5.0.0
- https://github.com/yahoo/serialize-javascript/releases/tag/v7.0.5
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-400, CWE-834- Platform
- npm
- Package
serialize-javascript- Disclosed
- 27.03.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-qj8w-gfj5-8c6v - CC BY 4.0
Vulnerability history: serialize-javascript
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 6
- First → latest
- 12.2019 09.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 2
- Medium 3
- Low 1
Disclosures per year
- 2019: 1
- 2020: 1
- 2021: 0
- 2022: 0
- 2023: 0
- 2024: 0
- 2025: 1
- 2026: 3
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