Is CVE-2025-21590 being actively exploited?

Yes. CVE-2025-21590 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added on March 13, 2025.

What is the CVSS score for CVE-2025-21590?

CVE-2025-21590 has a CVSS 3.1 base score of 4.4 (MEDIUM).

CVE-2025-21590

MEDIUM · CVSS 4.4CISA KEV: actively exploitedEPSS 1.7%EU EUVD: exploited

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.

Key facts

CVSS score: 4.4 (v3.1)
Severity: MEDIUM
CVSS vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N
Weakness (CWE): CWE-653
EPSS score: 1.7% (77th percentile)
In CISA KEV: Yes, added March 13, 2025
In EU EUVD: Yes (EUVD-2025-6303)
Published: March 12, 2025
NVD last modified: October 1, 2026
Status: Analyzed

CISA Known Exploited Vulnerability

Juniper Junos OS Improper Isolation or Compartmentalization Vulnerability

Added to the KEV catalog on March 13, 2025; federal remediation due April 3, 2025.

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2025-6303 in the EU Vulnerability Database. ENISA flags it as known exploited. Last updated in EUVD on February 26, 2026.

View on the EU Vulnerability Database

Affected products

juniper / junos
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and 29 more…

Certified products that may be affected

5 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.

Junos Space Network Management Platform, with or without Network Director and with or without Security Director in JA2500 - Juniper Networks, Inc. - FIPS 140 3816 - historical
Juniper Networks SRX345/SRX345-DUAL-AC with Junos 15.1X49-D110 - Juniper Networks, Inc. - FIPS 140 3247 - historical
Junos-FIPS 10.4 L2 OS Cryptographic Module - Juniper Networks, Inc. - FIPS 140 1813 - historical
Junos-FIPS 10.4 L1 OS Cryptographic Module - Juniper Networks, Inc. - FIPS 140 1772 - historical
JUNOS-FIPS - Juniper Networks, Inc. - FIPS 140 602 - historical

References

https://cloud.google.com/blog/topics/threat-intelligence/china-nexus-espionage-targets-juniper-routers(Third Party Advisory)
https://supportportal.juniper.net/JSA93446(Vendor Advisory)
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-21590(US Government Resource)

Last updated October 3, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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