What is CVE-2025-21590?

CVE-2025-21590 is a medium-severity vulnerability in Juniper Networks Junos Os, classified under CWE-653. CVSS score: 4.4/10. Published 2025-03-12.

How severe is CVE-2025-21590?

Medium severity. CVSS v3 base score is 4.4 out of 10.

Is CVE-2025-21590 known to be exploited?

Yes. CVE-2025-21590 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-03-13), indicating it is being actively exploited. 4 public proof-of-concept repositories are indexed.

Vulnerability in Juniper Networks Junos Os

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 ab…

EPSS: 0.017 (82.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.4 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N.

Affected products

Juniper Networks Junos Os — versions 0, 21.4, 22.2

Weakness classification (CWE)

CWE-653

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2025-03-13. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2025-04-03.

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.

Public proof-of-concept exploits

References

supportportal.juniper.net/JSA93446 (vendor-advisory)
cloud.google.com/blog/topics/threat-intelligence/china-nexus-espionage-targets-… (third-party-advisory)

Frequently asked questions

What is CVE-2025-21590?: CVE-2025-21590 is a medium-severity vulnerability in Juniper Networks Junos Os, classified under CWE-653. CVSS score: 4.4/10. Published 2025-03-12.
How severe is CVE-2025-21590?: Medium severity. CVSS v3 base score is 4.4 out of 10.
Is CVE-2025-21590 known to be exploited?: Yes. CVE-2025-21590 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-03-13), indicating it is being actively exploited. 4 public proof-of-concept repositories are indexed.