CVE-2025-21590

high-risk

Published 2025-03-12

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.

Do I need to act?

0.77% chance of exploitation

EPSS score — low exploit probability

CISA KEV: actively exploited in the wild

On the Known Exploited Vulnerabilities catalog — federal agencies must patch

Patch status unknown

Check vendor advisories for fix availability and mitigation guidance

CVSS 4.4/10 Medium

LOCAL / LOW complexity

Affected Products (20)

Junos

Affected Vendors

Juniper

References (3)

Third Party Advisory https://cloud.google.com/blog/topics/threat-intelligence/china-nexus-espionage-t...

Vendor Advisory https://supportportal.juniper.net/JSA93446

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

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high-risk

Severity 15/34 · Moderate

Exploitability 10/34 · Low

Exposure 29/34 · Critical