---
id: GHSA-9mqv-5hh9-4cgg
title: >-
  Node.js Adapter for Hono: Unauthenticated memory-leak DoS via aborted
  WebSocket handshake
summary: >-
  Node.js Adapter for Hono: Unauthenticated memory-leak DoS via aborted
  WebSocket handshake
severity: medium
cvss: 5.3
cwe:
  - CWE-401
  - CWE-770
vendor: hono
product: '@hono/node-server'
ecosystem: npm
affected:
  - '@hono/node-server >= 2.0.0, <= 2.0.9'
patched:
  - '@hono/node-server 2.0.10'
published: '2026-07-21'
updated: '2026-07-21'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-9mqv-5hh9-4cgg'
references:
  - url: >-
      https://github.com/honojs/node-server/security/advisories/GHSA-9mqv-5hh9-4cgg
  - url: >-
      https://github.com/honojs/node-server/commit/3a21938c418340e980cb7ffa88e78369f78392d1
  - url: 'https://github.com/honojs/node-server/releases/tag/v2.0.10'
  - url: 'https://github.com/advisories/GHSA-9mqv-5hh9-4cgg'
tags:
  - ghsa
  - npm
ingestedAt: '2026-07-21T22:55:08.587Z'
---

## Overview

## Summary

A WebSocket upgrade request to an `upgradeWebSocket` route with a missing or malformed `Sec-WebSocket-Key` header leaks memory permanently. The request's `IncomingMessage` is retained in an internal map and a pending promise is never settled, even though no connection is established. Since the route is reachable pre-handshake without authentication, an unauthenticated attacker can flood it to gradually exhaust memory.

## Details

The built-in WebSocket helper cleans up its internal map only on a successful handshake or when the route guard rejects the request. When `ws` aborts the handshake because `Sec-WebSocket-Key` is missing or malformed, no `connection` event is emitted, so neither cleanup path runs and the entry is retained forever. A present-but-malformed key leaks identically, so a proxy that only checks for the header's presence does not mitigate it.

## Impact

An unauthenticated attacker can flood any public `upgradeWebSocket` route with malformed-key upgrade requests, causing unbounded memory growth and eventual loss of availability. No confidentiality or integrity impact.

Reported by @TarPeg007.

## Affected packages

- `@hono/node-server >= 2.0.0, <= 2.0.9`

## Remediation

Upgrade to a patched release:

- `@hono/node-server 2.0.10`