CVE-2025-21590: Juniper Junos OS Improper Isolation or Compartmentalization Vulnerability

CISA Known Exploited Vulnerabilities

Name

Juniper Junos OS Improper Isolation or Compartmentalization Vulnerability

Vendor

Juniper

Product

Junos OS

Added to the catalog

2025-03-13

Due date for US federal agencies

2025-04-03

Weaknesses

CWE-653

Catalog version

2026.10.30

Juniper Junos OS contains an improper isolation or compartmentalization vulnerability. This vulnerability could allows a local attacker with high privileges to inject arbitrary code.

Required action (CISA)

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Ransomware use: CISA does not mark known use of this vulnerability in ransomware campaigns.

Links in CISA's notes

• https://supportportal.juniper.net/s/article/2025-03-Out-of-Cycle-Security-Bulletin-Junos-OS-A-local-attacker-with-shell-access-can-execute-arbitrary-code-CVE-2025-21590?language=en_US
• https://nvd.nist.gov/vuln/detail/CVE-2025-21590

Read on 2026-11-02T23:39:54.475Z under licence cisa-kev-cc0@b0067899 from https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

NVD analysis

Status

Analyzed

Published

2025-03-12T14:15:15.447

Last modified

2026-10-01T18:23:34.867

Weaknesses

CWE-653

An Improper Isolation or Compartmentalization vulnerability in the kernel of Juniper Networks Junos OS allows a local attacker with high privileges to compromise the integrity of the device.

A local attacker with access to the shell is able to inject arbitrary code which can compromise an affected device.
This issue is not exploitable from the Junos CLI.
This issue affects Junos OS: 



* All versions before 21.2R3-S9,
* 21.4 versions before 21.4R3-S10, 
* 22.2 versions before 22.2R3-S6, 
* 22.4 versions before 22.4R3-S6, 
* 23.2 versions before 23.2R2-S3, 
* 23.4 versions before 23.4R2-S4,
* 24.2 versions before 24.2R1-S2, 24.2R2.

References

• https://cloud.google.com/blog/topics/threat-intelligence/china-nexus-espionage-targets-juniper-routers (Third Party Advisory)
• https://supportportal.juniper.net/JSA93446 (Vendor Advisory)
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-21590 (US Government Resource)

This product uses the NVD API but is not endorsed or certified by the NVD.

Read on 2026-11-02T23:42:22.836Z under licence nvd-api-terms-of-use@ff2a5288 from https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2025-21590

CVE record

Title (CNA)

Junos OS: An local attacker with shell access can execute arbitrary code

Assigner

juniper

State

PUBLISHED

Published

2025-03-12T13:59:43.038Z

Updated

2026-02-26T19:09:35.631Z

Problem types

CWE-653 Improper Isolation or Compartmentalization

An Improper Isolation or Compartmentalization vulnerability in the kernel of Juniper Networks Junos OS allows a local attacker with high privileges to compromise the integrity of the device.

A local attacker with access to the shell is able to inject arbitrary code which can compromise an affected device.
This issue is not exploitable from the Junos CLI.
This issue affects Junos OS: 



* All versions before 21.2R3-S9,
* 21.4 versions before 21.4R3-S10, 
* 22.2 versions before 22.2R3-S6, 
* 22.4 versions before 22.4R3-S6, 
* 23.2 versions before 23.2R2-S3, 
* 23.4 versions before 23.4R2-S4,
* 24.2 versions before 24.2R1-S2, 24.2R2.

References

• https://supportportal.juniper.net/JSA93446
• https://cloud.google.com/blog/topics/threat-intelligence/china-nexus-espionage-targets-juniper-routers

Read on 2026-11-03T02:15:11.142Z under licence cve-terms-of-use@81bfa2f3 from https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2025/21xxx/CVE-2025-21590.json

Defensive techniques (MITRE D3FEND)

D3FEND maps these defensive techniques to the weakness (CWE) that NVD lists for this CVE, through the digital artifacts the weakness affects. D3FEND does not say they stop this vulnerability.

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