GHSA-342q-2mc2-5gmp @jmondi/url-to-png enables capture screenshot of localhost web services (unauthenticated pages)

• npm @jmondi/url-to-png: < 2.1.2 → fixed in 2.1.2

Summary The maintainer been contemplating whether FTP or other protocols could serve as useful functionalities, but there may not be a practical reason for it since we are utilizing headless Chrome to capture screenshots. The argument is based on the assumption that this package can function as a service. The package includes an `ALLOW_LIST` where the host can specify which services the user is permitted to capture screenshots of. By default, capturing screenshots of web services running on localhost, 127.0.0.1, or the [::] is allowed. The maintainer is of the opinion that the package should also have a blacklist due to a potential vulnerability (or rather design oversight). If someone hosts this on a server, users could then capture screenshots of other web services running locally. Unless this is strictly for web pages. Something similar here: https://github.com/follow-redirects/follow-redirects/issues/235 (localhost is intended for end users or hosts to deny, and the package is for HTTP/HTTPS.) This is marked as a `LOW` since the maintainer is not sure if this is a vulnerability, but it's still best to highlight it. :) PoC Have a service like so running locally: ```js const http = require("http") const server = http.createServer((req, res) => { console.log("Received headers:", req.headers) res.writeHead(200, { "Content-Type": "text/plain" }) res.end("Something private! But Hello from Server 2 :)") }) server.listen(3001, () => { console.log("Server two running on http://localhost:3001") }) ``` Run the package in dev mode, `pnpm dev`. Feed these URLs: ``` http://localhost:3089/?url=http://[::]:3001&width=4000 http://localhost:3089/?url=http://localhost:3001&width=4000 http://localhost:3089/?url=http://127.0.01:3001&width=4000 ``` Impact Disclose internal web services?