CVE-2026-92081fastify vulnerable to Denial of Service via unhandled exception on HTTP/2 trailer responses
Updated under an hour ago ()
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It affects fastify. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 5.9 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-248
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- openjs
- NVD analysis
- Awaiting Analysis
- Record last updated
- Sep 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
fastify fastify fastify:fastify (from the name) | before 5.12.5; 5.12.5 not affected | CNA record |
References
- https://github.com/fastify/fastify/security/advisories/GHSA-4mh8-r7rc-xpvc
- https://cna.openjsf.org/security-advisories.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.