CVE-2026-92081Network attack vectorHinoki check available

Unauthenticated server crash via HTTP/2 trailers

Published Sep 16, 2026 · Updated Sep 16, 2026

Denial of service in Fastify before 5.12.5 allows remote attackers to crash HTTP/2 servers by requesting routes that use trailers. The reply.trailer() path unconditionally adds the HTTP/1.1 Transfer-Encoding: chunked header, causing Node.js to throw during HTTP/2 header serialization without a catch. Exposure requires HTTP/2 and a reachable trailer-enabled route; one unauthenticated request terminates the process and drops all in-flight requests.

CVSS severityUnavailable
Unscored
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Denial of service in Fastify before 5.12.5 allows remote attackers to crash HTTP/2 servers by requesting routes that use trailers. The reply.trailer() path unconditionally adds the HTTP/1.1 Transfer-Encoding: chunked header, causing Node.js to throw during HTTP/2 header serialization without a catch. Exposure requires HTTP/2 and a reachable trailer-enabled route; one unauthenticated request terminates the process and drops all in-flight requests.

The record

CVE
CVE-2026-92081
Published
Sep 16, 2026
Updated
Sep 16, 2026
Vendor
Fastify
Product
Fastify
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <5.12.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fastify · Fastifyversion=0 <5.12.5

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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