URL Redirection to Untrusted Site ('Open Redirect')
macaron before 1.3.7 has an open redirect in the static handler, as demonstrated by the http://127.0.0.1:4000//example.com/ URL.
CWE-601 - Open Redirect
An open redirect attack employs a URL parameter, HTML refresh tags, or a DOM based location change to exploit the trust of a vulnerable domain to direct the users to a malicious website. The attack could lead to higher severity vulnerabilities such as unauthorized access control, account takeover, XSS, and more.