title: Junos OS: PTX Series: FPCs may restart unexpectedly upon receipt of specific MPLS packets with certain multi-unit interface configurations
description: An Improper Handling of Exceptional Conditions vulnerability on specific PTX Series devices, including the PTX1000, PTX3000 (NextGen), PTX5000, PTX10002-60C, PTX10008, and PTX10016 Series, in Juniper Networks Junos OS allows an unauthenticated MPLS-based attacker to cause a Denial of Service (DoS) by triggering the dcpfe process to crash and FPC to restart. On affected PTX Series devices, processing specific MPLS packets received on an interface with multiple units configured may cause FPC to restart unexpectedly. Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. This issue only affects PTX Series devices utilizing specific FPCs found on PTX1000, PTX3000 (NextGen), PTX5000, PTX10002-60C, PTX10008, and PTX10016 Series devices, only if multiple units are configured on the ingress interface, and at least one unit has 'family mpls' *not* configured. See the configuration sample below for more information. No other platforms are affected by this vulnerability. This issue affects: Juniper Networks Junos OS on PTX Series: All versions prior to 19.1R3-S9; 19.2 versions prior to 19.2R3-S6; 19.3 versions prior to 19.3R3-S6; 19.4 versions prior to 19.4R3-S8; 20.1 versions prior to 20.1R3-S4; 20.2 versions prior to 20.2R3-S5; 20.3 versions prior to 20.3R3-S4; 20.4 versions prior to 20.4R3-S4; 21.1 versions prior to 21.1R3-S2; 21.2 versions prior to 21.2R3-S1; 21.3 versions prior to 21.3R3; 21.4 versions prior to 21.4R2; 22.1 versions prior to 22.1R2.
problem types: CWE-755 Improper Handling of Exceptional Conditions
affected:
{
platforms: PTX Series
product: Junos OS
vendor: Juniper Networks
versions:
lessThan: 19.1R3-S9, status: affected, version: unspecified, versionType: custom
lessThan: 19.2R3-S6, status: affected, version: 19.2, versionType: custom
lessThan: 19.3R3-S6, status: affected, version: 19.3, versionType: custom
lessThan: 19.4R3-S8, status: affected, version: 19.4, versionType: custom
lessThan: 20.1R3-S4, status: affected, version: 20.1, versionType: custom
lessThan: 20.2R3-S5, status: affected, version: 20.2, versionType: custom
lessThan: 20.3R3-S4, status: affected, version: 20.3, versionType: custom
lessThan: 20.4R3-S4, status: affected, version: 20.4, versionType: custom
lessThan: 21.1R3-S2, status: affected, version: 21.1, versionType: custom
lessThan: 21.2R3-S1, status: affected, version: 21.2, versionType: custom
lessThan: 21.3R3, status: affected, version: 21.3, versionType: custom
lessThan: 21.4R2, status: affected, version: 21.4, versionType: custom
lessThan: 22.1R2, status: affected, version: 22.1, 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 19.1R3-S9, 19.2R3-S6, 19.3R3-S6, 19.4R3-S8, 20.1R3-S4, 20.2R3-S5, 20.3R3-S4, 20.4R3-S4, 21.1R3-S2, 21.2R3-S1, 21.3R3, 21.4R2, 22.1R2, 22.2R1, and all subsequent releases.
workarounds: The FPC crash only occurs if specific MPLS packets are received on an interface with multiple units configured and at least one unit has family mpls not configured. Also, the first unit with family mpls configured is not the lowest numerical unit on that interface.
A viable config-based workaround would be to reorder the unit numbers on core-facing interfaces to ensure the numerically lowest unit has 'family mpls' configured.