GHSA-x7j8-49r8-mr43High

@nevware21/ts-utils: Prototype Pollution in objDeepCopy/objCopyProps via for...in without hasOwnProperty

Published
May 21, 2026
Last Modified
May 21, 2026

🔗 CVE IDs covered (1)

📋 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.

🎯 Affected products1

  • npm/@nevware21/ts-utils:<= 0.13.0

🔗 References (2)