title: Junos OS Evolved: ACX7000 Series: Specific IPv6 transit traffic gets exceptioned to the routing-engine which causes increased CPU utilization
description: An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS Evolved on ACX7000 Series allows an unauthenticated network-based attacker to cause a partial Denial of Service (DoS). On receipt of specific IPv6 transit traffic, Junos OS Evolved on ACX7100-48L, ACX7100-32C and ACX7509 sends this traffic to the Routing Engine (RE) instead of forwarding it, leading to increased CPU utilization of the RE and a partial DoS. This issue only affects systems configured with IPv6. This issue does not affect ACX7024 which is supported from 22.3R1-EVO onwards where the fix has already been incorporated as indicated in the solution section. This issue affects Juniper Networks Junos OS Evolved on ACX7100-48L, ACX7100-32C, ACX7509: 21.1-EVO versions prior to 21.1R3-S2-EVO; 21.2-EVO versions prior to 21.2R3-S2-EVO; 21.3-EVO versions prior to 21.3R3-EVO; 21.4-EVO versions prior to 21.4R1-S1-EVO, 21.4R2-EVO. This issue does not affect Juniper Networks Junos OS Evolved versions prior to 21.1R1-EVO.
problem types: CWE-754 Improper Check for Unusual or Exceptional Conditions
affected:
{
vendor: Juniper Networks
product: Junos OS Evolved
versions:
version: unspecified, lessThan: 21.1R1-EVO, status: unaffected, versionType: custom
version: 21.1-EVO, status: affected, lessThan: 21.1R3-S2-EVO, versionType: custom
version: 21.2-EVO, status: affected, lessThan: 21.2R3-S2-EVO, versionType: custom
version: 21.3-EVO, status: affected, lessThan: 21.3R3-EVO, versionType: custom
version: 21.4-EVO, status: affected, lessThan: 21.4R1-S1-EVO, 21.4R2-EVO, versionType: custom
platforms: ACX7100-48L, ACX7100-32C, ACX7509
}
metrics:
cvssV3_1: [
version: 3.1
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
attackVector: NETWORK
attackComplexity: LOW
privilegesRequired: NONE
userInteraction: NONE
scope: UNCHANGED
confidentialityImpact: NONE
integrityImpact: NONE
availabilityImpact: LOW
baseScore: 5.3
baseSeverity: MEDIUM
]
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: 21.1R3-S2-EVO, 21.2R3-S2-EVO, 21.3R3-EVO, 21.4R1-S1-EVO, 21.4R2-EVO, 22.1R1-EVO, and all subsequent releases.
workarounds: There are no viable workarounds for this issue.