GHSA-2g4f-4pwh-qvx6

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GHSA-2g4f-4pwh-qvx6

Summary: ajv has ReDoS when using `$data` option

Details: ajv (Another JSON Schema Validator) through version 8.17.1 is vulnerable to Regular Expression Denial of Service (ReDoS) when the `$data` option is enabled. The pattern keyword accepts runtime data via JSON Pointer syntax (`$data` reference), which is passed directly to the JavaScript `RegExp()` constructor without validation. An attacker can inject a malicious regex pattern (e.g., `\"^(a|a)*$\"`) combined with crafted input to cause catastrophic backtracking. A 31-character payload causes approximately 44 seconds of CPU blocking, with each additional character doubling execution time. This enables complete denial of service with a single HTTP request against any API using ajv with `$data`: true for dynamic schema validation.

References: https://nvd.nist.gov/vuln/detail/CVE-2025-69873, https://github.com/ajv-validator/ajv/pull/2586, https://github.com/ajv-validator/ajv/pull/2588, https://github.com/ajv-validator/ajv/pull/2590, https://github.com/github/advisory-database/pull/6991, https://github.com/ajv-validator/ajv/commit/720a23fa453ffae8340e92c9b0fe886c54cfe0d5, https://github.com/EthanKim88/ethan-cve-disclosures/blob/main/CVE-2025-69873-ajv-ReDoS.md, https://github.com/advisories/GHSA-2g4f-4pwh-qvx6, https://github.com/ajv-validator/ajv, https://github.com/ajv-validator/ajv/releases/tag/v6.14.0, https://github.com/ajv-validator/ajv/releases/tag/v8.18.0