`Undici.ProxyAgent` never verifies the remote server's certificate, and always exposes all request & response data to the proxy. This unexpectedly means that proxies can MitM all HTTPS traffic, and if the proxy's URL is HTTP then it also means that nominally HTTPS requests are actually sent via plain-text HTTP between Undici and the proxy server.
https://hackerone.com/reports/1583680
https://github.com/nodejs/undici/security/advisories/GHSA-pgw7-wx7w-2w33