CVE Vulnerabilities

CVE-2026-25521

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

Published: Feb 04, 2026 | Modified: Feb 20, 2026
CVSS 3.x
8.8
HIGH
Source:
NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CVSS 2.x
RedHat/V2
RedHat/V3
9.3 CRITICAL
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Ubuntu
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Locutus brings stdlibs of other programming languages to JavaScript for educational purposes. In versions from 2.0.12 to before 2.0.39, a prototype pollution vulnerability exists in locutus. 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 String.prototype. This issue has been patched in version 2.0.39.

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
LocutusLocutus2.0.12 (including)2.0.39 (excluding)

Potential Mitigations

References