Vulnerability details

CVE-2025-21590

Actively exploited

Juniper Networks Junos OS

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

CVSS 4.0

6.7Medium

Remedy

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. (due: 2025-04-03)

Versions not listed as affected in the CVE record:

Junos OS — version 21.2R3-S9 and later
Junos OS — version 21.4R3-S10 and later
Junos OS — version 22.2R3-S6 and later
Junos OS — version 22.4R3-S6 and later
Junos OS — version 23.2R2-S3 and later
Junos OS — version 23.4R2-S4 and later

Official 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.

CVSS scores

Score	Version	Source	Vector
6.7Medium	4.0	CVEProject cvelistV5 (CNA) (juniper)	`CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N`
4.4Medium	3.1	CVEProject cvelistV5 (CNA) (juniper)	`CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N`

Affected products

Vendor	Product	Versions	Source
Juniper Networks	Junos OS	v < 21.2R3-S9	CVEProject cvelistV5 (CNA)
Juniper Networks	Junos OS	21.4 ≤ v < 21.4R3-S10	CVEProject cvelistV5 (CNA)
Juniper Networks	Junos OS	22.2 ≤ v < 22.2R3-S6	CVEProject cvelistV5 (CNA)
Juniper Networks	Junos OS	22.4 ≤ v < 22.4R3-S6	CVEProject cvelistV5 (CNA)
Juniper Networks	Junos OS	23.2 ≤ v < 23.2R2-S3	CVEProject cvelistV5 (CNA)
Juniper Networks	Junos OS	23.4 ≤ v < 23.4R2-S4	CVEProject cvelistV5 (CNA)
Juniper Networks	Junos OS	24.2 ≤ v < 24.2R1-S2, 24.2R2	CVEProject cvelistV5 (CNA)

References and advisories

https://supportportal.juniper.net/JSA93446 vendor-advisory
https://cloud.google.com/blog/topics/threat-intelligence/china-nexus-espionage-targets-juniper-routers third-party-advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-21590 government-resource

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Details

Published: 2025-03-12
Last updated: 2026-02-26
State: Published
Assigner (CNA): juniper
Kolun priority: 70 · High

CISA KEV catalog

Date added: 2025-03-13
Due date: 2025-04-03
Used in ransomware: Unknown

Exploit prediction (EPSS)

1.74%

Probability of exploitation in 30 days

78.1%

Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable: No
Exploitation: Active
Technical impact: Total

Weaknesses (CWE)

CWE-653
Improper Isolation or Compartmentalization