Advisories for Npm/@Hono/Node-Server package

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.

On Windows hosts, an encoded backslash (%5C) in the request path decodes to , which the Windows path resolver treats as a separator. serve-static then resolves a single URL segment such as admin\secret.txt into a nested file under the root and serves it, letting an attacker read static files meant to be protected behind prefix-mounted middleware. Directory escape (..) remains blocked.

A path handling inconsistency in serveStatic allows protected static files to be accessed by using repeated slashes (//) in the request path. When route-based middleware (e.g., /admin/*) is used for authorization, the router may not match paths containing repeated slashes, while serveStatic resolves them as normalized paths. This can lead to a middleware bypass.

When using @hono/node-server's static file serving together with route-based middleware protections (e.g. protecting /admin/*), inconsistent URL decoding can allow protected static resources to be accessed without authorization. In particular, paths containing encoded slashes (%2F) may be evaluated differently by routing/middleware matching versus static file path resolution, enabling a bypass where middleware does not run but the static file is still served.

The application hangs when receiving a Host header with a value that @hono/node-server can't handle well. Invalid values are those that cannot be parsed by the URL as a hostname such as an empty string, slashes /, and other strings. For example, if you have a simple application: import { serve } from '@hono/node-server' import { Hono } from 'hono' const app = new Hono() app.get('/', (c) => c.text('Hello')) serve(app) …

@hono/node-server is an adapter that allows users to run Hono applications on Node.js. Since v1.3.0, @hono/node-server has used its own Request object with url behavior that is unexpected. In the standard API, if the URL contains .., here called "double dots", the URL string returned by Request will be in the resolved path. However, the url in @hono/node-server's Request as does not resolve double dots, so http://localhost/static/.. /foo.txt is returned. …