This vulnerability involves a missing release of memory after its effective lifetime in the l2ald process of Juniper Networks Junos OS and Junos OS Evolved. In EVPN-MPLS deployments, memory allocated for ESI routes learned from remote multi-homed PE devices is not freed properly during route churn, causing a memory leak. Over time, this leak leads to the l2ald process crashing and restarting, resulting in a Denial of Service condition. The issue affects all versions before 22.4R3-S5, 23.2 versions before 23.2R2-S3, 23.4 versions before 23.4R2-S4, and 24.2 versions before 24.2R2 for both Junos OS and Junos OS Evolved. The vulnerability has a CVSS 3.1 base score of 6.5 with an attack vector of adjacent network, no privileges required, no user interaction, and impacts availability only. Juniper manages remediation for this cloud-hosted service.

An adjacent unauthenticated attacker can cause a memory leak in the l2ald process, which ultimately leads to the process crashing and restarting. This results in a Denial of Service (DoS) affecting the availability of the affected Junos OS or Junos OS Evolved device. There is no impact on confidentiality or integrity according to the CVSS vector.

A patch is available for this vulnerability in the specified fixed versions of Junos OS and Junos OS Evolved. Since this is a cloud service, Juniper Networks manages remediation server-side. Users should verify that their devices are running a fixed version at or beyond 22.4R3-S5, 23.2R2-S3, 23.4R2-S4, or 24.2R2 as applicable. Monitoring memory consumption of the l2ald process using the provided command can help detect abnormal memory usage. Check the official Juniper advisory for the latest remediation guidance.