jodit: Prototype pollution in Jodit via Jodit.modules.Helpers.set()

Summary

Jodit.modules.Helpers.set(chain, value, obj) walks the dot-separated chain, creating and following each path segment, without filtering prototype-mutating keys. A chain that begins with (or contains) __proto__, constructor, or prototype lets the final assignment reach and mutate Object.prototype (prototype pollution).

### Affected - Package: jodit (npm) - Versions: < 4.12.26 - Public API: Jodit.modules.Helpers.set(chain, value, obj)

Proof of

Concept ``js const { Jodit } = require('jodit'); delete Object.prototype.polluted; Jodit.modules.Helpers.set('__proto__.polluted', 'yes', {}); console.log(({}).polluted); // "yes" (before the fix) delete Object.prototype.polluted; ``

Impact

Applications that pass a user-controlled or partially user-controlled key path into Jodit.modules.Helpers.set() could be vulnerable to prototype pollution (CWE-1321): unexpected property injection, logic bypass, denial of service, or secondary security issues.

Patch

Fixed in 4.12.26 by rejecting any chain whose segments include __proto__, constructor, or prototype, reusing the same guard introduced for Jodit.configure() in 4.12.18.

Credit

Responsibly reported by Junming Wu.