2026-07 Security Bulletin: Junos OS and Junos OS Evolved: EX Series, QFX Series, MX Series: A specific 'show l2-learning/ethernet-switching' command causes l2ald crash (CVE-2026-57025)

Product Affected

This issue affects all versions of Junos OS and Junos OS Evolved. Affected platforms: EX Series, QFX Series, MX Series.

Severity

Medium

Severity Assessment (CVSS) Score

CVSS: v3.1: 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
CVSS: v4.0: 6.8 (CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/RE:M)

Problem

A Return of Pointer Value Outside of Expected Range vulnerability in the fileio library of Juniper Networks Junos OS and Junos OS Evolved allows a local, low-privilged attacker to cause a Denial-of-Service (DoS).

On EX Series, QFX Series and MX Series a low-privileged attacker issuing a specific 'show l2-learning' or 'show ethernet-switching' command will cause an l2ald crash which will lead to a temporary service impact for all layer 2 services until the process has automatically restarted.

This issue affects EX Series, QFX Series, MX Series:
Junos OS:

all versions before 23.2R2-S7,
23.4 versions before 23.4R2-S7,
24.2 versions before 24.2R2,
24.4 versions before 24.4R1-S2.

Junos OS Evolved:

all versions before 23.2R2-S7-EVO,
23.4 versions before 23.4R2-S8-EVO,
24.2 versions before 24.2R2-EVO,
24.4 versions before 24.4R1-S3-EVO.

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was found during internal product security testing or research.

This issue has been assigned CVE-2026-57025.

Solution

The following software releases have been updated to resolve this specific issue:
Junos OS: 23.2R2-S7, 23.4R2-S7, 24.2R2, 24.4R1-S2, 24.4R2, 25.2R1, and all subsequent releases;
Junos OS Evolved: 23.2R2-S7-EVO, 23.4R2-S8-EVO, 24.2R2-EVO, 24.4R1-S3-EVO, 24.4R2-EVO, 25.2R1-EVO, and all subsequent releases.

This issue is being tracked as 1861779 which is visible on the Customer Support website.

Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).

Workaround

There are no known workarounds for this issue.

To reduce the risk of exploitation use access lists or firewall filters to limit access to the CLI only from trusted hosts and administrators.

Severity Assessment

Information for how Juniper Networks uses CVSS can be found at KB 16446 [juniper.net] "Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories."

Modification History

2026-07-08: Initial Publication