CVE-2020-15366: Prototype Pollution in Ajv

Severity: medium (CVSS 5.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-07-15 · updated 2026-06-17
Weakness: CWE-1321

Description

An issue was discovered in ajv.validate() in Ajv (aka Another JSON Schema Validator) 6.12.2. A carefully crafted JSON schema could be provided that allows execution of other code by prototype pollution. (While untrusted schemas are recommended against, the worst case of an untrusted schema should be a denial of service, not execution of code.)

Affected products

ajv.js ajv: 6.12.2
Npm Ajv: before 6.12.3 — fixed in 6.12.3

How to fix

Upgrade to a fixed version: Npm Ajv 6.12.3. Check the vendor advisory for mitigations.

References

https://github.com/ajv-validator/ajv/releases/tag/v6.12.3
https://github.com/ajv-validator/ajv/tags
https://hackerone.com/bugs?subject=user&report_id=894259
https://security.netapp.com/advisory/ntap-20240621-0007/
https://github.com/ajv-validator/ajv/releases/tag/v6.12.3
https://github.com/ajv-validator/ajv/tags
https://hackerone.com/bugs?subject=user&report_id=894259
https://security.netapp.com/advisory/ntap-20240621-0007/

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