CVE-2025-21590
Juniper Junos OS Improper Isolation or Compartmentalization Vulnerability
This vulnerability is in the CISA Known Exploited Vulnerabilities catalog: attackers are using it. If you run Junos OS, fix it now.
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.
US federal civilian agencies must remediate by Apr 3, 2025.
Patch status
No official fix confirmed yet
Until a fix ships, follow the vendor's mitigations and CISA's required action, limit exposure of affected systems, and watch this record for a patch.
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.
Source: NIST National Vulnerability Database. Official vulnerability data, reproduced as published.
Affected products
| Product | Vendor | Source |
|---|---|---|
| Junos OS | Juniper | KEV |
Sources: KEV = CISA Known Exploited Vulnerabilities catalog. Version details have not been published yet.
Intelligence timeline
Developments from the last 30 days, newest first.
- CVSS scoredUpdateKEV
CVE-2025-21590 scored CVSS 6.7: Juniper Junos OS, Juniper Junos OS Improper Isolation or Compartmentalization Vulnerability
CISA lists this as exploited in the wild. Unpatched Junos OS systems are exposed to active attacks now.
Basis: NIST National Vulnerability Database
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Coverage
We have not published a story about this vulnerability yet.