What’s Vulnerable › Vulnerabilities

CVE-2022-21190: Prototype Pollution

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 4.0% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2022-05-13 · updated 2026-06-17
• Weakness: CWE-1321

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.

Affected products

• convict: before 6.2.3 — fixed in 6.2.3

How to fix

Upgrade to a fixed version: convict 6.2.3. Check the vendor advisory for mitigations.

References

• 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://github.com/mozilla/node-convict/commit/1ea0ab19c5208f66509e1c43b0d0f21c1fd29b75
• https://snyk.io/vuln/SNYK-JS-CONVICT-2774757
• 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://github.com/mozilla/node-convict/commit/1ea0ab19c5208f66509e1c43b0d0f21c1fd29b75
• https://snyk.io/vuln/SNYK-JS-CONVICT-2774757

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