CVE-2025-21590

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

MEDIUM

4.4

CVSS Score

Published: March 12, 2025 at 01:59 PM UTC

Updated: October 1, 2026 at 06:23 PM UTC

1 product affected across 1 vendorJunos

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Severity

MEDIUM4.4

Exploitation

CISA KEV

Exploit prediction

EPSS 2%

SSVC

Active

Actively Exploited

CISA Known Exploited Vulnerabilities (KEV) Catalog

EPSS Score1.7%

EPSS (Exploit Prediction Scoring System) estimates a 1.7% chance this CVE is exploited in the wild within the next 30 days — higher than 78% of all CVEs. It complements CVSS: a high EPSS on a mid-severity CVE can still be urgent.

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

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

Unknown

Added to KEV

Mar 13, 2025

Remediation Due

Apr 3, 2025

577 days overdue

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

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Junos · Juniper Networks

95%

v < 21.2v < 21.2R3-S921.4 ≤ v < 21.4R3-S1022.2 ≤ v < 22.2R3-S622.4 ≤ v < 22.4R3-S623.2 ≤ v < 23.2R2-S323.4 ≤ v < 23.4R2-S424.2 ≤ v < 24.2R1-S2, 24.2R221.2 21.2 r1 21.2 r1-s1 21.2 r1-s2 21.2 r2 21.2 r2-s1 21.2 r2-s2 21.2 r3 21.2 r3-s1 21.2 r3-s2 21.2 r3-s3 21.2 r3-s4 21.2 r3-s5 21.2 r3-s6 21.2 r3-s7 21.2 r3-s8 21.4 21.4 r1 21.4 r1-s1 21.4 r1-s2 21.4 r2 21.4 r2-s1 21.4 r2-s2 21.4 r3 21.4 r3-s1 21.4 r3-s2 21.4 r3-s3 21.4 r3-s4 21.4 r3-s5 21.4 r3-s6 21.4 r3-s7 21.4 r3-s8 21.4 r3-s9 22.2 22.2 r1 22.2 r1-s1 22.2 r1-s2 22.2 r2 22.2 r2-s1 22.2 r2-s2 22.2 r3 22.2 r3-s1 22.2 r3-s2 22.2 r3-s3 22.2 r3-s4 22.2 r3-s5 22.4 22.4 r1 22.4 r1-s1 22.4 r1-s2 22.4 r2 22.4 r2-s1 22.4 r2-s2 22.4 r3 22.4 r3-s1 22.4 r3-s2 22.4 r3-s3 22.4 r3-s4 22.4 r3-s5 23.2 23.2 r1 23.2 r1-s1 23.2 r1-s2 23.2 r2 23.2 r2-s1 23.2 r2-s2 23.4 23.4 r1 23.4 r1-s1 23.4 r1-s2 23.4 r2 23.4 r2-s1 23.4 r2-s2 23.4 r2-s3 24.2 24.2 r1 24.2 r1-s1 24.2 r2

Affected range stops below 21.2, so it looks safe — our inference, not a vendor statement

Affected range stops below 21.2R3-S9, so it looks safe — our inference, not a vendor statement

Affected range stops below 21.4R3-S10, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.2R3-S6, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.4R3-S6, so it looks safe — our inference, not a vendor statement

Affected range stops below 23.2R2-S3, so it looks safe — our inference, not a vendor statement

Affected range stops below 23.4R2-S4, so it looks safe — our inference, not a vendor statement

Affected range stops below 24.2R1-S2, 24.2R2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

https://supportportal.juniper.net/JSA93446

References (3)

Third Party Advisory

Source: [email protected]

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

Vendor Advisory

Source: [email protected]

https://supportportal.juniper.net/JSA93446

US Government Resource

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-21590

SSVC — Action Prioritization

SSVCActiveNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.4MEDIUMjuniper

Attack Vector: LOCAL
Complexity: LOW
Privileges: HIGH
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: NONE
Integrity: HIGH
Availability: NONE

Vector?

Quick Info

StatusANALYZED

CWE

CWE-653

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