The Quagga BGP daemon (bgpd) prior to version 1.2.3 has a bug in its parsing of "Capabilities" in BGP OPEN messages, in the bgp_packet.c:bgp_capability_msg_parse function. The parser can enter an infinite loop on invalid capabilities if a Multi-Protocol capability does not have a recognized AFI/SAFI, causing a denial of service.
Exploitability
AV:NAC:LPR:LUI:NScope
S:UImpact
C:NI:NA:H6.5/CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HOther