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Fencer Intel
medium 5.3

CVE-2026-126343 json

@hono/node-server: Unhandled `ECONNRESET` on the socket during an asynchronous WebSocket upgrade crashes the process

published 11d ago modified 3h ago also EUVD-2026-124721 , GHSA-qv5m-9pm6-hqp3

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

@hono/node-server allows running the Hono application on Node.js. From 2.0.0 until 2.1.6, the WebSocket upgrade handler waits for the Hono application to finish asynchronous middleware or handler work without first attaching an error listener to the socket. If an unauthenticated client resets the TCP connection during that window, the socket emits an unhandled ECONNRESET error and terminates the Node.js process. If a global uncaughtException handler suppresses termination, the pending upgrade waiter is not released and repeated requests can grow the heap. This affects applications that enable WebSocket support and perform asynchronous work on the upgrade path. This issue is fixed in version 2.1.6.

Patch / fix

  • npm @hono/node-server 2.1.6

Is CVE-2026-126343 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
4h ago

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-13).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
npm @hono/node-server
>=2.0.0, <2.1.6
2.1.6

Affected products

  • honojs node-server

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of honojs/node-server published their own advisory on GitHub. Reviewed sources take precedence over it.