
All the credit is due to the RFC’s authors: A. Azimov (Qrator Labs & Yandex), E. Bogomazov (Qrator Labs), R. Bush (IIJ & Arrcus), K. Patel (Arrcus), K. Sriram.
A BGP route leak is an unintentional propagation of BGP prefixes beyond the intended scope that could result in a redirection of traffic through an unintended path that may enable eavesdropping or traffic analysis, and may or may not result in an overload or complete drop (black hole) of the traffic. Route leaks can be accidental or malicious but most often arise from accidental misconfigurations.