title: MX Series: L2ALD daemon may crash if a duplicate MAC is learned by two different interfaces
description: If a duplicate MAC address is learned by two different interfaces on an MX Series device, the MAC address learning function correctly flaps between the interfaces. However, the Layer 2 Address Learning Daemon (L2ALD) daemon might crash when attempting to delete the duplicate MAC address when the particular entry is not found in the internal MAC address table. This issue only occurs on MX Series devices with l2-backhaul VPN configured. No other products or platforms are affected by this issue. Affected releases are Juniper Networks Junos OS: 15.1 versions prior to 15.1R7-S1 on MX Series; 16.1 versions prior to 16.1R4-S12, 16.1R6-S6 on MX Series; 16.2 versions prior to 16.2R2-S7 on MX Series; 17.1 versions prior to 17.1R2-S9 on MX Series; 17.2 versions prior to 17.2R1-S7, 17.2R2-S6 on MX Series; 17.3 versions prior to 17.3R2-S4, 17.3R3-S1 on MX Series; 17.4 versions prior to 17.4R1-S5 on MX Series; 18.1 versions prior to 18.1R2 on MX Series.
problem types: Denial of service
affected:
{
platforms: MX Series
product: Junos OS
vendor: Juniper Networks
versions:
lessThan: 15.1R7-S1, status: affected, version: 15.1, versionType: custom
lessThan: 16.1R4-S12, 16.1R6-S6, status: affected, version: 16.1, versionType: custom
lessThan: 16.2R2-S7, status: affected, version: 16.2, versionType: custom
lessThan: 17.1R2-S9, status: affected, version: 17.1, versionType: custom
lessThan: 17.2R1-S7, 17.2R2-S6, status: affected, version: 17.2, versionType: custom
lessThan: 17.3R2-S4, 17.3R3-S1, status: affected, version: 17.3, versionType: custom
lessThan: 17.4R1-S5, status: affected, version: 17.4, versionType: custom
lessThan: 18.1R2, status: affected, version: 18.1, versionType: custom
}
metrics:
cvssV3_0: [
attackComplexity: LOW
attackVector: ADJACENT_NETWORK
availabilityImpact: HIGH
baseScore: 6.5
baseSeverity: MEDIUM
confidentialityImpact: NONE
integrityImpact: NONE
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
version: 3.0
]
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: 15.1R7-S1, 16.1R4-S12, 16.1R6-S6, 16.1R7, 16.2R2-S7, 16.2R3, 17.1R2-S9, 17.1R3, 17.2R1-S7, 17.2R2-S6, 17.2R3, 17.3R2-S4, 17.3R3-S1, 17.4R1-S5, 17.4R2, 18.1R2, 18.2R1, and all subsequent releases.
This fix has also been proactively committed into Junos OS: 15.1X49-D150, 15.1X53-D235, 15.1X53-D495, 15.1X53-D590, 15.1X53-D68, 18.2X75-D5, and all subsequent releases.
workarounds: There are no viable workarounds for this issue