CVE-2026-33780

published 2026-04-09

CVE-2026-33780: A Missing Release of Memory after Effective Lifetime vulnerability in the Layer 2 Address Learning Daemon (l2ald) of Juniper Networks Junos OS and Junos OS…

high 7.1 CVSS 4.0

AV A AC L AT N PR N UI N VC N VI N VA H SC N SI N SA L E X CR X IR X AR X MAV X MAC X MAT X MPR X MUI X MVC X MVI X MVA X MSC X MSI X MSA X S X AU Y R X V X RE M U X

A Missing Release of Memory after Effective Lifetime vulnerability in the Layer 2 Address Learning Daemon (l2ald) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent, unauthenticated attacker to cause a memory leak ultimately leading to a Denial of Service (DoS).

In an EVPN-MPLS scenario, routes learned from remote multi-homed Provider Edge (PE) devices are programmed as ESI routes. Due to a logic issue in the l2ald memory management, memory allocated for these routes is not released when there is churn for these routes. As a result, memory leaks in the l2ald process which will ultimately lead to a crash and restart of l2ald.

Use the following command to monitor the memory consumption by l2ald:

user@device> show system process extensive | match "PID|l2ald"

This issue affects:

Junos OS:

* all versions before 22.4R3-S5,
* 23.2 versions before 23.2R2-S3,
* 23.4 versions before 23.4R2-S4,
* 24.2 versions before 24.2R2;

Junos OS Evolved:

* all versions before 22.4R3-S5-EVO,
* 23.2 versions before 23.2R2-S3-EVO,
* 23.4 versions before 23.4R2-S4-EVO,
* 24.2 versions before 24.2R2-EVO.

Affected

9 ranges

Vendor	Product	Version range	Fixed in
juniper	junos_os	—	—
juniper_networks	junos_os	< 22.4R3-S5	22.4R3-S5
juniper_networks	junos_os	>= 23.2 < 23.2R2-S3	23.2R2-S3
juniper_networks	junos_os	>= 23.4 < 23.4R2-S4	23.4R2-S4
juniper_networks	junos_os	>= 24.2 < 24.2R2	24.2R2
juniper_networks	junos_os_evolved	>= 23.2 < 23.2R2-S3-EVO	23.2R2-S3-EVO
juniper_networks	junos_os_evolved	>= 23.4 < 23.4R2-S4-EVO	23.4R2-S4-EVO
juniper_networks	junos_os_evolved	>= 24.2 < 24.2R2-EVO	24.2R2-EVO
juniper_networks	junos_os_evolved	>= all version prior to < 22.4R3-S5-EVO	22.4R3-S5-EVO

CWE-401