CVE-2018-14505: Mitmweb in mitmproxy allows DNS Rebinding attacks

The vulnerability stemmed from improper host validation in mitmweb's web server setup. The pre-patch version in app.py's Application class registered handlers without host restrictions, enabling access via any domain name. The fix added DNS rebinding protection by: 1) Introducing a DnsRebind handler that blocks non-IP access, and 2) Restricting handler registration to only match IP/localhost patterns via regex. The Application.init function's original handler configuration was the root cause as it didn't validate request origins, making CWE-20 (Input Validation) applicable.