{"id":"CVE-2026-92081","published":"2026-09-16T09:17:10.137","lastModified":"2026-09-16T19:40:00.317","description":"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.","cvssScore":5.9,"cvssSeverity":"MEDIUM","cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","cwes":["CWE-248"],"vendors":[],"products":[],"references":[{"url":"https://cna.openjsf.org/security-advisories.html","tags":[]},{"url":"https://github.com/fastify/fastify/security/advisories/GHSA-4mh8-r7rc-xpvc","tags":[]}],"exploitRefs":[{"url":"https://github.com/fastify/fastify/security/advisories/GHSA-4mh8-r7rc-xpvc","tags":[]}],"hasPoc":true,"ai":null}