CVE-2026-46614: Fission router exposes /fission-function/<ns>/<name> on its public listener, allowing invocation of any function without an HTTPTrigger

The Fission router registers an internal-style route — /fission-function/<name> and /fission-function/<ns>/<name> — for every Function object, independent of whether any HTTPTrigger exists for that function. The route was mounted on the same listener as user-defined HTTPTriggers (svc/router, port 8888), so any caller who could reach the router could invoke any function by guessing its metadata.name (and namespace), bypassing the host / path / method / method-allow-list restrictions encoded in HTTPTrigger objects.