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, re
The following software releases have been updated to resolve this specific issue: Junos OS 18.2R3-S8, 18.3R3-S5, 18.4R1-S6, 18.4R3-S7, 19.1R3-S5, 19.2R2, 19.2R3, 19.3R3, 19.4R3, 20.1R2, 20.2R2, 20.3R1, and all subsequent releases.
There are no viable workarounds for this issue.
| Product | Vulnerable range | Fixed version | Advisory |
|---|---|---|---|
| Juniper Networks Junos OS | >=18.2<18.2R3-S8 | 18.2R3-S8 | advisory ↗ |
| Juniper Networks Junos OS | >=18.3<18.3R3-S5 | 18.3R3-S5 | advisory ↗ |
| Juniper Networks Junos OS | >=18.4<18.4R1-S6, 18.4R3-S7 | 18.4R1-S6, 18.4R3-S7 | advisory ↗ |
| Juniper Networks Junos OS | >=19.1<19.1R3-S5 | 19.1R3-S5 | advisory ↗ |
| Juniper Networks Junos OS | >=19.2<19.2R2, 19.2R3 | 19.2R2, 19.2R3 | advisory ↗ |
| Juniper Networks Junos OS | >=19.3<19.3R3 | 19.3R3 | advisory ↗ |
| Juniper Networks Junos OS | >=19.4<19.4R3 | 19.4R3 | advisory ↗ |
| Juniper Networks Junos OS | >=20.1<20.1R2 | 20.1R2 | advisory ↗ |
| Juniper Networks Junos OS | >=20.2<20.2R2 | 20.2R2 | advisory ↗ |