This affects the package convict before 6.2.3. This is a bypass of [CVE-2022-22143](https://security.snyk.io/vuln/SNYK-JS-CONVICT-2340604). The [fix](https://github.com/mozilla/node-convict/commit/3b86be087d8f14681a9c889d45da7fe3ad9cd880) introduced, relies on the startsWith method and does not prevent the vulnerability: before splitting the path, it checks if it starts with __proto__ or this.constructor.prototype. To bypass this check it's possible to prepend the dangerous paths with any string value followed by a dot, like for example foo.__proto__ or foo.this.constructor.prototype.
The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.
| Link | Tags |
|---|---|
| https://snyk.io/vuln/SNYK-JS-CONVICT-2774757 | exploit third party advisory |
| https://github.com/mozilla/node-convict/blob/3b86be087d8f14681a9c889d45da7fe3ad9cd880/packages/convict/src/main.js%23L571 | patch broken link third party advisory |
| https://gist.github.com/dellalibera/cebce20e51410acebff1f46afdc89808 | exploit third party advisory |
| https://github.com/mozilla/node-convict/blob/master/CHANGELOG.md%23623---2022-05-07 | tool signature release notes broken link |
| https://github.com/mozilla/node-convict/commit/1ea0ab19c5208f66509e1c43b0d0f21c1fd29b75 | tool signature patch |