GitHub Advisoryadvisory · npm

GHSA-x7j8-49r8-mr43 @nevware21/ts-utils: Prototype Pollution in objDeepCopy/objCopyProps via for...in without hasOwnProperty

HIGH Published 2026-05-21 Modified 2026-05-21 Official page ↗
Aliases
CVE-2026-46681
Ecosystem
npm
Packages
@nevware21/ts-utils
Severity
High
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U
Weaknesses
CWE-1321
Reviewed
2026-05-21

Affected packages

• npm @nevware21/ts-utils: < 0.14.0 → fixed in 0.14.0

Description

Summary The _copyProps function in lib/src/object/copy.ts uses for...in to iterate over source object properties without an Object.hasOwnProperty check, and does not filter dangerous keys (__proto__, constructor, prototype). This allows an attacker to pollute the prototype chain of all objects in the application. Details In _copyProps() (copy.ts lines 186-191), the code iterates all enumerable properties including inherited ones and dangerous keys like __proto__. Any object with a __proto__ key (e.g., from untrusted JSON input) will overwrite the target's prototype. PoC ``` const malicious = JSON.parse('{"__proto__": {"polluted": true}}'); objDeepCopy(malicious); console.log({}.polluted); // true ``` Suggested Fix Add objHasOwnProperty check and filter __proto__, constructor, prototype keys.

Related

Alias · CVE (1)

  • CVE-2026-46681 @nevware21/ts-utils is a comprehensive TypeScript/JavaScript utility library. vulnerability

Weakness · CWE (1)

  • CWE-1321 Improperly Controlled Modification of Object Prototype Attributes weakness

References