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. Specifically, in EVPN-MPLS scenarios, routes learned from remote multi-homed Provider Edge devices are programmed as ESI routes. Due to a logic error in memory management, memory allocated for these routes is not freed when route churn occurs, causing a memory leak. Over time, this leak leads to the crash and restart of the l2ald daemon, resulting in a Denial of Service condition. The issue affects all versions before 22.4R3-S5, certain 23.2, 23.4, and 24.2 releases, with patches available in later versions. The vulnerability requires no privileges or user interaction and can be triggered by an adjacent attacker.

The impact of this vulnerability is a Denial of Service caused by the crash and restart of the l2ald process due to memory exhaustion from a leak. There is no confidentiality or integrity impact reported. The attacker must be adjacent and unauthenticated. The CVSS 3.1 base score is 6.5 (medium severity), reflecting the availability impact without confidentiality or integrity loss.

A patch is available for this vulnerability in Junos OS and Junos OS Evolved versions 22.4R3-S5 and later, including specific updates for 23.2, 23.4, and 24.2 releases. Since this is a cloud-hosted service, Juniper manages remediation server-side. Users should verify that their systems are updated to the fixed versions to prevent exploitation. Monitor memory usage of the l2ald process using the provided command to detect abnormal consumption. Check the official Juniper advisory for the latest patch and remediation details.