Flareo no longer accepts third-party Dockerfiles for build and signing. The route stays so anyone who bookmarked it gets an honest explanation instead of a dead end.
Accepting an untrusted Dockerfile and signing the result put the signing identity one sandbox escape away from minting a Flareo-verified malicious image. An open build service is also an abuse magnet — free compute for cryptomining and staging — and an arbitrary Dockerfile (which can curl … | sh) contradicts reproducible builds. The full case is in the threat model.
Flareo re-publishes pinned upstream images with signatures and receipts. Point flareo verify at any public image — catalog or not — and check the Sigstore trail yourself.