title: Junos OS: QFX Series: The PFE may crash when a lot of MAC addresses are being learned and aged
description: A Use After Free vulnerability in the Layer 2 Address Learning Manager (l2alm) of Juniper Networks Junos OS on QFX Series allows an adjacent attacker to cause the Packet Forwarding Engine to crash and restart, leading to a Denial of Service (DoS). The PFE may crash when a lot of MAC learning and aging happens, but due to a Race Condition (Concurrent Execution using Shared Resource with Improper Synchronization) that is outside the attackers direct control. This issue affects: Juniper Networks Junos OS versions prior to 19.4R3-S10 on QFX Series; 20.2 versions prior to 20.2R3-S7 on QFX Series; 20.3 versions prior to 20.3R3-S6 on QFX Series; 20.4 versions prior to 20.4R3-S5 on QFX Series; 21.1 versions prior to 21.1R3-S4 on QFX Series; 21.2 versions prior to 21.2R3-S3 on QFX Series; 21.3 versions prior to 21.3R3-S3 on QFX Series; 21.4 versions prior to 21.4R3 on QFX Series; 22.1 versions prior to 22.1R3 on QFX Series; 22.2 versions prior to 22.2R2 on QFX Series.
problem types: CWE-362 Race Condition (Concurrent Execution using Shared Resource with Improper Synchronization)
affected:
{
vendor: Juniper Networks
product: Junos OS
versions:
version: unspecified, lessThan: 19.4R3-S10, status: affected, versionType: custom
version: 20.2, status: affected, lessThan: 20.2R3-S7, versionType: custom
version: 20.3, status: affected, lessThan: 20.3R3-S6, versionType: custom
version: 20.4, status: affected, lessThan: 20.4R3-S5, versionType: custom
version: 21.1, status: affected, lessThan: 21.1R3-S4, versionType: custom
version: 21.2, status: affected, lessThan: 21.2R3-S3, versionType: custom
version: 21.3, status: affected, lessThan: 21.3R3-S3, versionType: custom
version: 21.4, status: affected, lessThan: 21.4R3, versionType: custom
version: 22.1, status: affected, lessThan: 22.1R3, versionType: custom
version: 22.2, status: affected, lessThan: 22.2R2, versionType: custom
platforms: QFX Series
}
metrics:
cvssV3_1: [
version: 3.1
vectorString: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
attackVector: ADJACENT_NETWORK
attackComplexity: HIGH
privilegesRequired: NONE
userInteraction: NONE
scope: UNCHANGED
confidentialityImpact: NONE
integrityImpact: NONE
availabilityImpact: HIGH
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: 19.4R3-S10, 20.2R3-S7, 20.4R3-S5, 21.1R3-S4, 21.2R3-S3, 21.4R3, 22.1R3, 22.2R2, 22.3R1, and all subsequent releases.
workarounds: There are no known workarounds for this issue.