Cross-Site Scripting (XSS) medium risk
## Describe the bug

The koa package is vulnerable to Cross-Site Scripting (XSS). The redirect function in response.js outputs an HTML hyperlink of the supplied URL in the body of the redirect response without sanitizing the URL. An attacker can exploit this by inputting a JavaScript URL that would then be executed.

The application is vulnerable by using this component and passing unvalidated input to the redirect() method. Additionally, the vulnerability can only be exploited if a user is running an older browser.

Root Cause
koa-2.15.3.tgzpackage/lib/response.js[0.0.2, )

https://github.com/koajs/koa/issues/1250
https://github.com/koajs/koa/issues/1289
