route leak
When one or more Autonomous Systems (AS) issue incorrect information about the IP addresses on their networks. This causes inefficient routing and failures for both the originating organisation (e.g. an ISP or backbone provider) and others trying to route traffic through their networks.
A mallicious route leak is called a "route hijack" or "BGP hijack".
https://blog.thousandeyes.com/finding-and-diagnosing-bgp-route-leaks/. https://www.wired.com/story/how-a-tiny-error-shut-off-the-internet-for-parts-of-the-us/