Medium severity · published Apr 9, 2026
CVE-2026-33780
Junos OS and Junos OS Evolved: In an EVPN-MPLS scenario churn of ESI routes causes a memory leak in l2ald
6.5
CVSS
0.2%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 7% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
JO
Junos OS · Juniper
before 22.4R3-S5; 23.2 before 23.2R2-S3; 23.4 before 23.4R2-S4; 24.2 before 24.2R2 · source: vendor, NVD
JO
Junos OS Evolved · Juniper Networks
all version prior to before 22.4R3-S5-EVO; 23.2 before 23.2R2-S3-EVO; 23.4 before 23.4R2-S4-EVO; 24.2 before 24.2R2-EVO · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33780
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-33780
Vendor Advisory
https://kb.juniper.net/JSA107819
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