CVE Vulnerabilities

CVE-2026-26021

Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

Published: Feb 11, 2026 | Modified: Feb 13, 2026
CVSS 3.x
9.8
CRITICAL
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
RedHat/V2
RedHat/V3
Ubuntu
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set-in provides the set value of nested associative structure given array of keys. A prototype pollution vulnerability exists in the the npm package set-in (>=2.0.1, < 2.0.5). Despite a previous fix that attempted to mitigate prototype pollution by checking whether user input contained a forbidden key, it is still possible to pollute Object.prototype via a crafted input using Array.prototype. This has been fixed in version 2.0.5.

Weakness

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.

Affected Software

NameVendorStart VersionEnd Version
Set-inSet-in_project2.0.1 (including)2.0.5 (excluding)

Potential Mitigations

References