nomeus runs on your own machine and listens on loopback only (LoopbackOnly middleware on every route; mutations also need the X-Nomeus: 1 header, so a page you're browsing can't POST to it). valet trust gives it passwordless sudo for Valet's own commands — that's the sensitive part, and it's the same grant Valet itself asks for.

If you find a way for a site nomeus serves, a page you visit, or a nomeus.yml you didn't write to make nomeus do something on your behalf, don't open a public issue. Use GitHub's private vulnerability report for this repository. You'll get a reply within a week, and credit in the changelog unless you'd rather not.