CVE-2026-86818 fast-uri vulnerable to mailto header injection via percent-encoded field-name desynchronization

fast-uri is a dependency-free RFC 3986 URI parser for Node.js, used by Fastify and ajv, that added a mailto scheme parser in version 4.1.3. In versions 4.1.3 and 4.1.4, the mailto parser compares each query field name to the reserved names to, subject, and body while the name is still...