title: Junos OS: ACX5448, ACX710: BFD sessions might flap due to high rate of transit ARP packets
description: 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.
problem types: Denial of Service
affected:
{
platforms: ACX5448
product: Junos OS
vendor: Juniper Networks
versions:
lessThan: 18.2R3-S8, status: affected, version: 18.2, versionType: custom
lessThan: 18.3R3-S5, status: affected, version: 18.3, versionType: custom
lessThan: 18.4R1-S6, 18.4R3-S7, status: affected, version: 18.4, versionType: custom
lessThan: 19.1R3-S5, status: affected, version: 19.1, versionType: custom
lessThan: 19.2R2, 19.2R3, status: affected, version: 19.2, versionType: custom
lessThan: 19.3R3, status: affected, version: 19.3, versionType: custom
lessThan: 19.4R3, status: affected, version: 19.4, versionType: custom
lessThan: 20.1R2, status: affected, version: 20.1, versionType: custom
}
{
platforms: ACX5448, ACX710
product: Junos OS
vendor: Juniper Networks
versions:
lessThan: 20.2R2, status: affected, version: 20.2, versionType: custom
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: ADJACENT_NETWORK
availabilityImpact: HIGH
baseScore: 6.5
baseSeverity: MEDIUM
confidentialityImpact: NONE
integrityImpact: NONE
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
version: 3.1
]
exploits: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
solutions: 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.
workarounds: There are no viable workarounds for this issue.