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

Summary

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.

Timeline

1. Apr 9, 2026, 9:29 PM UTCCVE published
2. Apr 13, 2026, 5:39 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. Apr 13, 2026, 6:06 PM UTCRecord last updated

Affected versions

• Juniper Networks Junos OS

  fixed in 22.4R3-S5; From 23.2 · fixed in 23.2R2-S3; From 23.4 · fixed in 23.4R2-S4; From 24.2 · fixed in 24.2R2

• Juniper Networks Junos OS Evolved

  fixed in 22.4R3-S5-EVO; From 23.2 · fixed in 23.2R2-S3-EVO; From 23.4 · fixed in 23.4R2-S4-EVO; From 24.2 · fixed in 24.2R2-EVO

References 1