---
id: CVE-2025-21590
title: >-
  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 …
summary: >-
  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 …
severity: medium
cvss: 4.4
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N'
cwe:
  - CWE-653
vendor: juniper
product: junos
affected:
  - junos < 21.2
  - junos = 21.2
  - junos = 21.4
  - junos = 22.2
  - junos = 22.4
  - junos = 23.2
  - junos = 23.4
  - junos = 24.2
patched:
  - junos 21.2
published: '2025-03-12'
updated: '2026-10-01'
sourceUpdated: '2026-10-01T18:23:34.867'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-21590'
references:
  - url: >-
      https://cloud.google.com/blog/topics/threat-intelligence/china-nexus-espionage-targets-juniper-routers
    label: sirt@juniper.net
  - url: 'https://supportportal.juniper.net/JSA93446'
    label: sirt@juniper.net
  - url: >-
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-21590
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - kev
  - in-the-wild
epss: 0.01735
epssPercentile: 0.77544
kev: true
kevDateAdded: '2025-03-13'
kevDueDate: '2025-04-03'
kevRansomware: false
exploited: true
zeroDay: true
ingestedAt: '2026-10-01T18:55:42.279Z'
---

## Overview

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.

## Affected

- `junos < 21.2`
- `junos = 21.2`
- `junos = 21.4`
- `junos = 22.2`
- `junos = 22.4`
- `junos = 23.2`
- `junos = 23.4`
- `junos = 24.2`

## Remediation

Upgrade past the affected range:

- `junos 21.2`