fastify is a fast and low overhead web framework for Node.js. Versions of fastify before 5.12.1 are affected by a schema validation bypass when a request body schema targets a root primitive value. W…

Summary

fastify is a fast and low overhead web framework for Node.js. Versions of fastify before 5.12.1 are affected by a schema validation bypass when a request body schema targets a root primitive value. When the schema validates a top-level primitive such as an integer, Ajv can coerce a JSON string into the expected type during validation, but Fastify does not replace the root request body with the coerced value, so the route handler receives the original unvalidated string. As a result, a request t…