Description

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.

Known Exploited

🚨 Marked as known exploited on March 13th, 2025 (about 1 month ago).

Classification

CVE ID: CVE-2025-21590

CVSS Base Severity: MEDIUM

CVSS Base Score: 4.4

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

Affected Products

Vendor: Juniper Networks

Product: Junos OS

Exploit Prediction Scoring System (EPSS)

EPSS Score: 5.1% (probability of being exploited)

EPSS Percentile: 88.89% (scored less or equal to compared to others)

EPSS Date: 2025-04-10 (when was this score calculated)

Stakeholder-Specific Vulnerability Categorization (SSVC)

SSVC Exploitation: none

SSVC Technical Impact: total

SSVC Automatable: false

References

https://nvd.nist.gov/vuln/detail/CVE-2025-21590
https://supportportal.juniper.net/JSA93446
https://cloud.google.com/blog/topics/threat-intelligence/china-nexus-espionage-targets-juniper-routers

Timeline