This affects the package convict before 6.2.3. This is a bypass of CVE-2022-22143. The fix 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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2022-21190
• mozilla/node-convict@1ea0ab1
• https://gist.github.com/dellalibera/cebce20e51410acebff1f46afdc89808
• https://github.com/mozilla/node-convict/blob/3b86be087d8f14681a9c889d45da7fe3ad9cd880/packages/convict/src/main.js%23L571
• https://github.com/mozilla/node-convict/blob/master/CHANGELOG.md%23623---2022-05-07
• https://snyk.io/vuln/SNYK-JS-CONVICT-2774757