url-parse incorrectly parses hostname / protocol due to unstripped leading control characters.

Leading control characters in a URL are not stripped when passed into url-parse. This can cause input URLs to be mistakenly be interpreted as a relative URL without a hostname and protocol, while the WHATWG URL parser will trim control characters and treat it as an absolute URL.

If url-parse is used in security decisions involving the hostname / protocol, and the input URL is used in a client which uses the WHATWG URL parser, the decision may be incorrect.

This can also lead to a cross-site scripting (XSS) vulnerability if url-parse is used to check for the javascript: protocol in URLs. See following example:

const parse = require('url-parse')
const express = require('express')
const app = express()
const port = 3000

url = parse(\"\\bjavascript:alert(1)\")

console.log(url)

app.get('/', (req, res) => {
 if (url.protocol !== \"javascript:\") {res.send(\"<a href>CLICK ME!</a>\")}
 })

app.listen(port, () =&gt; {
 console.log(`Example app listening on port ${port}`)
 })