bgpd/bgp_flowspec.c in FRRouting (FRR) before 8.4.3 mishandles an nlri length of zero, aka a "flowspec overflow."
https://lists.debian.org/debian-lts-announce/2024/04/msg00019.html
https://github.com/FRRouting/frr/pull/12884
https://github.com/FRRouting/frr/compare/frr-8.4.2...frr-8.4.3