CVE-2022-21190: Mozilla Convict

Critical severity, CVSS 9.8. EPSS: 4% chance of exploitation in the next 30 days.

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.

Affected products

• Mozilla Convict: before 6.2.3 (fixed in 6.2.3)

Published 2022-05-13. Last modified 2026-06-17.