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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.

PUBLISHED Reserved 2024-12-26 | Published 2025-03-12 | Updated 2026-02-26 | Assigner juniper




MEDIUM: 4.4CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N

MEDIUM: 6.7CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

CISA Known Exploited Vulnerability

Date added 2025-03-13 | Due date 2025-04-03

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Problem types

CWE-653 Improper Isolation or Compartmentalization

Product status

Default status
unaffected

Any version before 21.2R3-S9
affected

21.4 (semver) before 21.4R3-S10
affected

22.2 (semver) before 22.2R3-S6
affected

22.4 (semver) before 22.4R3-S6
affected

23.2 (semver) before 23.2R2-S3
affected

23.4 (semver) before 23.4R2-S4
affected

24.2 (semver) before 24.2R1-S2, 24.2R2
affected

Timeline

2025-03-12:Initial Publication
2025-03-12:Corrected hotlinks for CVSS assessments
2025-03-14:Rephrased sentences on Amazon involvement to reduce the chance for confusion
2025-04-09:Updated solution section to clarify which platforms are not fixed in all but only in specific releases
2025-04-14:For the products/platforms specifically mentioned in the solution section: Please note that Junos OS version 21.2R3-S9.20, which was made available last week, does not address the issue completely. We'll publish an updated version with the complete fix and update this advisory as soon as possible.
2025-05-06:For the products/platforms specifically mentioned in the solution section: Please note that Junos OS version 21.2R3-S9.21 has been publish with the complete fix.

Credits

Juniper SIRT would like to acknowledge and thank Matteo Memelli from Amazon for responsibly reporting this issue. Note: Amazon found the issue during internal security research and not due to exploitation. reporter

References

www.cisa.gov/...erabilities-catalog?field_cve=CVE-2025-21590 government-resource

supportportal.juniper.net/JSA93446 vendor-advisory

cloud.google.com/...-nexus-espionage-targets-juniper-routers third-party-advisory

cve.org (CVE-2025-21590)

nvd.nist.gov (CVE-2025-21590)

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