ajv (Another JSON Schema Validator) before 8.18.0 is vulnerable to...
Vulnerability Description
ajv (Another JSON Schema Validator) before 8.18.0 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. This issue is also fixed in version 6.14.0.
Impact Analysis
Refer to official advisory for detailed impact metrics.
Remediation
Ensure systems are updated to the latest vendor-supplied patch levels.
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Credits & Attribution
No credits recorded in the NVD database.
References
- https://github.com/advisories/GHSA-2g4f-4pwh-qvx6
- https://github.com/EthanKim88/ethan-cve-disclosures/blob/main/CVE-2025-69873-ajv-ReDoS.md
- https://github.com/github/advisory-database/pull/6991
- https://github.com/ajv-validator/ajv/pull/2588
- https://github.com/ajv-validator/ajv/releases/tag/v6.14.0
- https://github.com/ajv-validator/ajv/pull/2590
Affected Vendor
ajv.js
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