A vulnerability in Juniper Networks Junos OS running on the ACX5448 and ACX710 platforms may cause BFD sessions to flap when a high rate of transit ARP packets are received. This, in turn, may impact routing protocols and network stability, leading to a Denial of Service (DoS) condition. When a high rate of transit ARP packets are exceptioned to the CPU and BFD flaps, the following log messages may be seen: bfdd[15864]: BFDD_STATE_UP_TO_DOWN: BFD Session 192.168.14.3 (IFL 232) state Up - Down LD/RD(17/19) Up time:11:38:17 Local diag: CtlExpire Remote diag: None Reason: Detect Timer Expiry. bfdd[15864]: BFDD_TRAP_SHOP_STATE_DOWN: local discriminator: 17, new state: down, interface: irb.998, peer addr: 192.168.14.3 rpd[15839]: RPD_ISIS_ADJDOWN: IS-IS lost L2 adjacency to peer on irb.998, reason: BFD Session Down bfdd[15864]: BFDD_TRAP_SHOP_STATE_UP: local discriminator: 17, new state: up, interface: irb.998, peer addr: 192.168.14.3 This issue only affects the ACX5448 Series and ACX710 Series routers. No other products or platforms are affected by this vulnerability. This issue affects Juniper Networks Junos OS: 18.2 versions prior to 18.2R3-S8 on ACX5448.

18.3 versions prior to 18.3R3-S5 on ACX5448.

18.4 versions prior to 18.4R1-S6, 18.4R3-S7 on ACX5448.

19.1 versions prior to 19.1R3-S5 on ACX5448.

19.2 versions prior to 19.2R2, 19.2R3 on ACX5448.

19.3 versions prior to 19.3R3 on ACX5448.

19.4 versions prior to 19.4R3 on ACX5448.

20.1 versions prior to 20.1R2 on ACX5448.

20.2 versions prior to 20.2R2 on ACX5448 and ACX710.