Bug 2535071 (CVE-2026-92081) - CVE-2026-92081 fastify: fastify: Denial of Service via unhandled exception on HTTP/2 trailer responses
Summary: CVE-2026-92081 fastify: fastify: Denial of Service via unhandled exception on...
Keywords:
Status: NEW
Alias: CVE-2026-92081
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-16 09:11 UTC by OSIDB Bzimport
Modified: 2026-09-24 14:04 UTC (History)
2 users (show)

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Description OSIDB Bzimport 2026-09-16 09:11:32 UTC
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.


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