CVE-2026-26021
Prototype Pollution in set-in npm Package Allows Object Manipulation
Publication date: 2026-02-11
Last updated on: 2026-02-13
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| set-in_project | set-in | From 2.0.1 (inc) to 2.0.5 (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?
The vulnerability is a prototype pollution issue in the npm package set-in versions 2.0.1 to before 2.0.5. The package provides functionality to set values in nested associative structures using an array of keys. Despite a previous fix that tried to prevent prototype pollution by blocking certain forbidden keys, attackers can still exploit the vulnerability by crafting inputs that use Array.prototype to pollute Object.prototype.
How can this vulnerability impact me? :
This vulnerability can allow an attacker to modify the Object.prototype, which can lead to unexpected behavior in applications using the set-in package. Such prototype pollution can cause security issues like privilege escalation, denial of service, or arbitrary code execution depending on how the polluted prototype is used in 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 prototype pollution vulnerability in the npm package set-in, you should upgrade the package to version 2.0.5 or later, where the issue has been fixed.