# CVE-2025-21590

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.

- Page: https://www.vulneraibility.com/cve/CVE-2025-21590
- CVSS: 4.4
- Known exploited: yes, in CISA KEV since 2025-03-13; CISA due date 2025-04-03
- EPSS: 1.75%
- CISA SSVC: exploitation active, automatable no, technical impact total (assessed 2025-03-14)
- Weakness: CWE-653
- Published: 2025-03-12

## Affected versions

- Juniper Networks Junos OS: affected < 21.2R3-S9; >= 21.4 and < 21.4R3-S10; >= 22.2 and < 22.2R3-S6; >= 22.4 and < 22.4R3-S6; >= 23.2 and < 23.2R2-S3; >= 23.4 and < 23.4R2-S4; >= 24.2 and < 24.2R1-S2, 24.2R2

A version outside these ranges is not a statement that it is unaffected.

## References

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

---
Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.