CVE-2022-21190: mozilla convict Prototype Pollution

Vulnerability summary

CVE-2022-21190 is a critical (CVSS 9.8) Prototype Pollution vulnerability in mozilla convict. EPSS estimates a 3.97% chance of exploitation in the next 30 days, higher than 90.3% of scored vulnerabilities. 2 public exploits are recorded.

Timeline

1. 13-05-2022
   PublishedVulnerability first disclosed.
2. 17-09-2024
   Last modifiedVulnerability information updated.

Description

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.

• CWE-1321Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')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.