Route leak
termnetworkingISP & telecom
Re-announcing routes beyond their intended scope - typically passing routes learned from one transit provider or peer to another - so a network briefly claims to be a path to far more of the internet than it can carry.
Leaks are usually accidents and are responsible for a large share of the biggest routing outages on record: traffic for major services converges on a network with a fraction of the required capacity and simply drops. The distinction from a hijack is intent, not mechanism, and the defence is identical - prefix filtering by the upstream. The recurring lesson is that the failure is rarely the leaking network; it is the larger provider that accepted and propagated an announcement it should have discarded.
Also known as: as path leak, transit leak, reannouncement