CVE-2026-33780 MEDIUM

CVE-2026-33780: Junos OS and Junos OS Evolved: In an EVPN-MPLS scenario churn of ESI routes causes a memory leak in l2ald

Vendor Juniper Networks
Product Junos OS
Weakness CWE-401
Published April 9, 2026
Last update April 13, 2026

CVSS base score

6.5/10
Attack vector Adjacent
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

April 9, 2026 CVE published
April 13, 2026 Record updated