Juniper Junos OS Improper Isolation or Compartmentalization Vulnerability
Juniper Networks — Junos OS
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.
4.4
1.7%
Vector breakdown
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N
- Published
- Mar 12, 2025
- Modified
- Feb 26, 2026
- Added to KEV
- Mar 13, 2025
- Federal patch due
- Apr 3, 2025
CISA 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.
Weakness classification
Proof-of-concept & exploitation references
Weaponization
Public repositories whose name or description references CVE-2025-21590, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit - cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.
No public GitHub repositories referencing CVE-2025-21590 were found at last check. Absence here is not proof no exploit exists - see the references below for vendor advisories and write-ups.
References
Frequently asked questions
What is 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.
How severe is CVE-2025-21590?
CVE-2025-21590 has a CVSS base score of 4.4 out of 10 (CVSS 3.1).
Is CVE-2025-21590 actively exploited in the wild?
Yes. CVE-2025-21590 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Mar 13, 2025, meaning CISA has confirmed evidence of active exploitation.
What is the EPSS score for CVE-2025-21590?
1.7% - meaning FIRST.org's EPSS model estimates a 1.7% probability this vulnerability will be exploited in the wild within 30 days (74% percentile among all scored CVEs).
What type of vulnerability is CVE-2025-21590?
CVE-2025-21590 is classified under CWE-653 (CWE-653 Improper Isolation or Compartmentalization).
Cross-checked against
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