CVE-2026-25521
Prototype Pollution in Locutus stdlibs Enables Object Prototype Manipulation
Publication date: 2026-02-04
Last updated on: 2026-02-20
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| locutus | locutus | From 2.0.12 (inc) to 2.0.39 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-1321 | The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is a prototype pollution issue in the Locutus library, which provides standard libraries of other programming languages for JavaScript. In versions from 2.0.12 up to but not including 2.0.39, an attacker can manipulate the Object.prototype by crafting a malicious input that exploits String.prototype, bypassing previous mitigation attempts that checked for forbidden keys.
How can this vulnerability impact me? :
The vulnerability allows an attacker to pollute the Object.prototype, which can lead to unexpected behavior in JavaScript applications using the affected Locutus versions. This can result in security issues such as privilege escalation, denial of service, or arbitrary code execution depending on how the polluted prototype is used within the application.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, you should upgrade Locutus to version 2.0.39 or later, where the prototype pollution issue has been patched.