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

CVE-2026-33780 · Severity: medium · CVSS 6.5 · Published 2026-04-09

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.

Technologies: Juniper Junos, Juniper Junos Os Evolved. Vendors: Juniper.

Quick answers

Is CVE-2026-33780 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-33780 being exploited in the wild.
How severe is CVE-2026-33780?
Medium severity, with a CVSS score of 6.5, published 9 April 2026.
Which products and versions are affected?
Juniper Junos, Juniper Junos Os Evolved. The advisory does not name versions.
Is there a fix for CVE-2026-33780?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
Am I affected by CVE-2026-33780?
Check whether you run Juniper Junos or Juniper Junos Os Evolved. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Affected products

  • Juniper Junos
  • Juniper Junos Os Evolved

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