CVE-2026-33780
published 2026-04-09CVE-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…
PriorityP429medium6.5CVSS 3.1
AVAACLPRNUINSUCNINAH
EPSS
0.17%
7.0th percentile
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
19 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| juniper | junos | < 22.4 | 22.4 |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos | — | — |
| juniper | junos_os | — | — |
| juniper | junos_os_evolved | < 22.4 | 22.4 |
| juniper | junos_os_evolved | — | — |
| juniper | junos_os_evolved | — | — |
| juniper | junos_os_evolved | — | — |
| juniper | junos_os_evolved | — | — |
| 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 |
CVSS provenance
nvdv3.16.5MEDIUMCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvdv4.07.1HIGHCVSS: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
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Juniper
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 Jun
vendor_juniper·2026-04-09·CVSS 6.5
CVE-2026-33780 [MEDIUM] CWE-401 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 Jun
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 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|l2a
VulDB
Juniper Junos OS/Junos OS Evolved prior 22.4R3-S5/23.2R2-S3/23.4R2-S4/24.2R2 Layer 2 Address Learning Daemon memory leak (JSA107819)
vuldb·2026-04-10·CVSS 7.1
CVE-2026-33780 [HIGH] Juniper Junos OS/Junos OS Evolved prior 22.4R3-S5/23.2R2-S3/23.4R2-S4/24.2R2 Layer 2 Address Learning Daemon memory leak (JSA107819)
A vulnerability described as problematic has been identified in Juniper Junos OS and Junos OS Evolved. This affects an unknown part of the component Layer 2 Address Learning Daemon. Such manipulation leads to memory leak.
This vulnerability is uniquely identified as CVE-2026-33780. The attack can only be initiated within the local network. No exploit exists.
Upgrading the affected component is recommended.
GHSA
GHSA-wcmx-9w9j-q7ph: A Missing Release of Memory after Effective Lifetime vulnerability in the Layer 2 Address Learning Daemon (l2ald) of Juniper Networks Junos OS and Jun
ghsa_unreviewed·2026-04-10
CVE-2026-33780 [HIGH] CWE-401 GHSA-wcmx-9w9j-q7ph: A Missing Release of Memory after Effective Lifetime vulnerability in the Layer 2 Address Learning Daemon (l2ald) of Juniper Networks Junos OS and Jun
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
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2026-04-09
Published