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JunosOperating system · Juniper

CVE-2026-57025

MEDIUM · 5.5 CVSS v3.1 Published 2026-07-09
Fix available
A fix is available. Upgrade to 23.2 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click 6 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A Return of Pointer Value Outside of Expected Range vulnerability exists in the fileio library of Juniper Networks Junos OS and Junos OS Evolved. A local, low-privileged attacker can trigger a crash of the l2ald process by issuing specific 'show l2-learning' or 'show ethernet-switching' commands, causing denial of service for all layer 2 services until the process automatically restarts.

MitigationApply the vendor-supplied patches: Junos OS versions 23.2R2-S7, 23.4R2-S7, 24.2R2, or 24.4R1-S2 and later; Junos OS Evolved versions 23.2R2-S7-EVO, 23.4R2-S8-EVO, 24.2R2-EVO, or 24.4R1-S3-EVO and later.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
JunosOperating system
Affected:< 23.2= 23.2= 23.4= 24.2= 24.4
Junos Os EvolvedOperating system
Affected:< 23.2= 23.2= 23.4= 24.2= 24.4

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the Junos OS version
    Run 'show version' or 'request system version' to obtain the exact installed version of Junos OS or Junos OS Evolved
    Affected if The installed version matches < 23.2, or equals 23.2, 23.4, 24.2, or 24.4 without the vendor patch applied (23.2R2-S7, 23.4R2-S7, 24.2R2, or 24.4R1-S2 and later for Junos OS; 23.2R2-S7-EVO, 23.4R2-S8-EVO, 24.2R2-EVO, or 24.4R1-S3-EVO and later for Junos OS Evolved)
  2. Confirm the l2ald process is active
    Run 'show system processes' or check process status for l2ald daemon
    Affected if The l2ald process is running, which is required for the denial of service to occur
  3. Verify layer 2 learning features are configured
    Run 'show l2-learning interfaces' or 'show ethernet-switching interface' to check if Layer 2 learning or Ethernet switching is enabled
    Affected if Layer 2 learning or Ethernet switching features are active, as these are required for the vulnerable code path to be exercised
  4. Test for crash condition using the trigger commands
    Execute 'show l2-learning' and 'show ethernet-switching' commands and observe if the l2ald process crashes or becomes unresponsive
    Affected if The commands cause the l2ald process to crash or hang, confirming the vulnerability is present

If the Junos OS/Evolved version is in the affected list (before 23.2R2-S7/23.2R2-S7-EVO, or equal to 23.2/23.4/24.2/24.4 without the corresponding patch) AND layer 2 services are enabled, the environment is vulnerable to denial of service via the specified commands.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 23.2 or later
Fixed in 23.2
Interim mitigation

Apply the vendor-supplied patches: Junos OS versions 23.2R2-S7, 23.4R2-S7, 24.2R2, or 24.4R1-S2 and later; Junos OS Evolved versions 23.2R2-S7-EVO, 23.4R2-S8-EVO, 24.2R2-EVO, or 24.4R1-S3-EVO and later.

Recommended fix High confidence

Junos OS: 23.2R2-S7 / 23.4R2-S7 / 24.2R2 / 24.4R1-S2 or later; Junos OS Evolved: 23.2R2-S7-EVO / 23.4R2-S8-EVO / 24.2R2-EVO / 24.4R1-S3-EVO or later

  1. 1. Identify the current Junos OS or Junos OS Evolved version installed on the device using 'show version' command
  2. 2. For Junos OS devices: Upgrade to one of the following fixed versions: 23.2R2-S7, 23.4R2-S7, 24.2R2, or 24.4R1-S2 (or later)
  3. 3. For Junos OS Evolved devices: Upgrade to one of the following fixed versions: 23.2R2-S7-EVO, 23.4R2-S8-EVO, 24.2R2-EVO, or 24.4R1-S3-EVO (or later)
  4. 4. After upgrade, verify the l2ald process is running normally using 'show system processes' or equivalent
  5. 5. Test that 'show l2-learning' and 'show ethernet-switching' commands execute without crashing
Caveat Standard Junos upgrade precautions apply - review release notes for any hardware-specific considerations and schedule maintenance window

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Junos Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-57025 in production — separate from our analysis above.

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