GHSA-9MQV-5HH9-4CGG
Vulnerability from github – Published: 2026-07-21 22:04 – Updated: 2026-08-13 17:37Summary
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": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 2.0.9"
},
"package": {
"ecosystem": "npm",
"name": "@hono/node-server"
},
"ranges": [
{
"events": [
{
"introduced": "2.0.0"
},
{
"fixed": "2.0.10"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-73565"
],
"database_specific": {
"cwe_ids": [
"CWE-401",
"CWE-770"
],
"github_reviewed": true,
"github_reviewed_at": "2026-07-21T22:04:27Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "## Summary\n\nA WebSocket upgrade request to an `upgradeWebSocket` route with a missing or malformed `Sec-WebSocket-Key` header leaks memory permanently. The request\u0027s `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.\n\n## Details\n\nThe 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\u0027s presence does not mitigate it.\n\n## Impact\n\nAn 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.\n\nReported by @TarPeg007.",
"id": "GHSA-9mqv-5hh9-4cgg",
"modified": "2026-08-13T17:37:34Z",
"published": "2026-07-21T22:04:27Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/honojs/node-server/security/advisories/GHSA-9mqv-5hh9-4cgg"
},
{
"type": "WEB",
"url": "https://github.com/honojs/node-server/commit/3a21938c418340e980cb7ffa88e78369f78392d1"
},
{
"type": "PACKAGE",
"url": "https://github.com/honojs/node-server"
},
{
"type": "WEB",
"url": "https://github.com/honojs/node-server/releases/tag/v2.0.10"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
"type": "CVSS_V3"
}
],
"summary": "Node.js Adapter for Hono: Unauthenticated memory-leak DoS via aborted WebSocket handshake"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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