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 he…
Historical advisory saved 30 Oct 2026 12:53:26 UTC. The publisher may have updated it since then. Latest advisory.
euvd · EUVD-2026-80315
Publishedfastify 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.
Additional publisher context
EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.
Original publisher date fields
datePublished: Sep 16, 2026, 8:52:49 AM
dateUpdated: Sep 16, 2026, 2:00:59 PM
- Source published
- Sep 16, 2026, 8:52:49 AM (timezone not stated)
- Source modified
- Sep 16, 2026, 2:00:59 PM (timezone not stated)
- Saved here
- 30 Oct 2026 12:53:26 UTC
- Source terms
- ENISA EUVD · source terms and attribution apply
Original source record · Cite this exact observation · Complete original publisher JSON
Source: euvd · ENISA EUVD · source terms and attribution apply. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.
EUVD CVSS 3.1 · 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H