CVE-2026-53719: Envoy Gateway: Nil-dereference when SecurityPolicy targets TCPRoute without spec.authorization

Vulnerability report without repro case. Repro case may be added later after harness is complete.

Preconditions (4):

• Tenant has SecurityPolicy + TCPRoute RBAC (baseline)
• Tenant namespace permitted to attach TCPRoute to a Gateway listener
• spec.authorization omitted (the trigger)
• No admission webhook blocks the shape

Description:

A namespace-scoped tenant can deterministically panic the gatewayapi runner on every reconcile with a single CRD; the recover() in message/watchutil.go:53 keeps the process alive but unwinds the entire handle() callback in runner/runner.go:192, so xDS/Infra IR publishing stalls controller-wide until an admin deletes the object. Data plane keeps serving last-good config.