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

Moderate severity GitHub Reviewed Published Mar 25, 2026 in yahoo/serialize-javascript • Updated Mar 31, 2026

Package

npm serialize-javascript (npm)

Affected versions

< 7.0.5

Patched versions

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.

References

@okuryu okuryu published to yahoo/serialize-javascript Mar 25, 2026
Published to the GitHub Advisory Database Mar 27, 2026
Reviewed Mar 27, 2026
Published by the National Vulnerability Database Mar 31, 2026
Last updated Mar 31, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(12th percentile)

Weaknesses

Uncontrolled Resource Consumption

The product does not properly control the allocation and maintenance of a limited resource. Learn more on MITRE.

Excessive Iteration

The product performs an iteration or loop without sufficiently limiting the number of times that the loop is executed. Learn more on MITRE.

CVE ID

CVE-2026-34043

GHSA ID

GHSA-qj8w-gfj5-8c6v

Credits

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