GHSA-rxrv-835q-v5mh
locutus is vulnerable to Prototype Pollution
Quick fix
GHSA-rxrv-835q-v5mh — locutus: upgrade to the fixed version with the command below.
npm install locutus@2.0.39Details
### Summary A Prototype Pollution vulnerability exists in the the npm package locutus (>2.0.12). Despite a previous fix that attempted to mitigate Prototype Pollution by checking whether user input contained a forbidden key, it is still possible to pollute Object.prototype via a crafted input using String.prototype. This issue was fixed in version 2.0.39.
### Details The vulnerability resides in line 77 to 79 of https://github.com/locutusjs/locutus/blob/main/src/php/strings/parse_str.js where includes() function is used to check whether user provided input contain forbidden strings.
### PoC
#### Steps to reproduce 1. Install latest version of locutus using npm install or cloning from git 2. Run the following code snippet:
```javascript String.prototype.includes = () => false; console.log({}.polluted); const locutus = require('locutus'); locutus.php.strings.parse_str('constructor[prototype][polluted]=yes'); console.log({}.polluted); // prints yes -> indicating that the patch was bypassed and Prototype Pollution occurred ```
#### Expected behavior Prototype Pollution should be prevented and {} should not gain new properties. This should be printed on the console: ``` undefined undefined OR throw an Error ```
#### Actual behavior Object.prototype is polluted This is printed on the console: ``` undefined yes ```
### Impact This is a Prototype Pollution vulnerability, which can have severe security implications depending on how locutus is used by downstream applications. Any application that processes attacker-controlled input using this `locutus.php.strings.parse_str` may be affected. It could potentially lead to the following problems: 1. Authentication bypass 2. Denial of service 3. Remote code execution (if polluted property is passed to sinks like eval or child_process)
Are you affected?
Enter the version of the package you're using.