CVE-2026-92081

Описание

fastify is a fast and low-overhead web framework for Node.js. In versions before 5.12.5, when a route registers a response trailer via reply.trailer() and is served over HTTP/2, fastify unconditionally sets the Transfer-Encoding: chunked header, which is forbidden on HTTP/2, so Node.js throws while serializing the response headers. The exception is not caught and becomes an uncaughtException, so a single unauthenticated HTTP/2 request to any route that uses trailers crashes the server process and drops all in-flight requests, and it can be repeated on every restart. The issue is fixed in fastify 5.12.5, and users should upgrade to 5.12.5 or later. As a workaround, avoid registering response trailers with reply.trailer() on routes served over HTTP/2 until upgrading.

A flaw was found in fastify. When a route registers a response trailer and is served over HTTP/2, fastify incorrectly sets the 'Transfer-Encoding: chunked' header. This leads to an unhandled exception in Node.js, causing the server process to crash and resulting in a Denial of Service (DoS). A remote, unauthenticated attacker can trigger this flaw with a single HTTP/2 request to any route using trailers, repeatedly crashing the server.